Disclaimer: I do not own Ben 10.

A/N: So the folks at discord snowballed the idea of Lucy using her shape-shifting powers to tease out what Ben likes in a girl. The results are enlightening. BWEN.

"Ben, I'm bored!" Lucy complained from where she'd stretched out on the couch, drawing out his name in her best attempt at a pitiful whine. The seventeen year old boy sitting on the other half of said couch just continued playing his handheld video game, not even twitching.

"How is that my problem?" He asked, unbothered.

"You're the host! You're supposed to entertain your guests!" She asserted, gesturing to herself imperiously. Again, no luck.

"If you wanted entertainment, maybe you should've stayed over at your other cousin's house. You know, the dweeb you like to tease? Has a spare bedroom so you don't have to share with me? And is a girl?" He returned, pointedly. "Because that would've made the walk-ins a lot less awkward."

Lucy snickered. Humans were always so touchy about the nudity thing, it was hilarious. And ridiculous. She could make her own 'clothing' from her body and look dressed while still being naked; like the simple dress she was wearing right now. But that never seemed to bother them as much. Weird folks. But the subject had gotten his attention, so...

"Some boys wouldn't mind walking in on a pretty girl." She countered, waggling her brows at him. "In fact, many of the boys at my school would kill to see what you're getting for free. Daily." She clucked her tongue at him, moving from her sprawl into a more seductive pose.

Ben glanced over and shamelessly ran his eyes up and down her form, knowing she wouldn't care. Inspection complete, he shrugged. "You're alright, mud butt. Just not my type."

...hellooo new line of questioning. "Really?" She asked, rearing up on all fours and crawling over to grin in his face. Ben studiously ignored her, even as she could see him start to turn faintly red under the scrutiny... and her proximity. She almost snickered. For all his denial, she still got under his skin.

Good. She liked being there. "What's your taste like, Ben?" She asked, eyes narrowing slyly.

She leaned further into his space, opening her mouth to nip at his jaw for giggles, only to be forestalled by a hand covering her mouth and pushing her away, causing her to tumble off the couch with a yelp. "Not blondes." Ben supplied above her, amusement coloring his voice.

Lucy grumbled from where she lay half sprawled off the couch, before sitting up on it with a grin, unfazed by this temporary setback. Alright Benny boy, it's on now.

She gave the boy a considering look. Let's see... he'd dated Julie for a while and still gave Kai long looks whenever she dropped by so…

She shifted her hair to black, and shuffled over to hover close again, drawing his attention away from his game. His frown quickly morphed into surprise, though. She smirked. "Is this better?" She purred.

The boy seemed to take a few seconds to process that before awkwardly coughing into his hand. "Err, yeah. It's okay."

She hummed. Yeah, definitely not paying attention to his game anymore, but also not quite flustered enough. She closed her eyes and focused, shifting them to brown. Opening them again, she was satisfied to see his breath hitch before his gaze turned suspicious. Not that him knowing what she was doing mattered in the slightest; she could still enjoy the effect she had on him. And see how far she could push him till he snapped.

Heck, she might even score a kiss out of it. That never hurt.

"So we have dark hair, soft brown eyes." She mused, wickedly. "I know! How about we lose some flab?"

"How about you get back to your side of the couch?"

"Hush you." She shifted again, altering her figure, feeling it harden. Whereas she preferred to have a more soft and curvy shape, both Kai and Julie were more toned than that- yup, now she was getting a lovely blush for her efforts. She grinned. "My my, I think I've found your type. Should've guessed, really."

Ben shook off the blush, composing himself, even as he pulled at his collar. "Eh, closer than you were, but I don't think I really even have a type."

No type? She doubted that. Even as a Lenopan, she knew falling for the same type of looks twice was kinda telling. But maybe it was more of a personality thing; maybe Ben just liked strong, sassy women that could kick his butt in a fight-

Hold up.

Hold riiiiight up.

She felt giddiness rise in her, lips curling into a grin. She'd planned to turn her hair silver next just to see if she could get that Charmcaster ball rolling, but maybe, just maybe…

She closed her eyes again, feeling Ben's cautious gaze on her. She shifted her body again, as well as her coloring. Alright, let's go a little paler, suck in the boobs a bit, bit more to that butt, muscles a little less defined buy still obvious, a freckle or two and for hair…

She opened her eyes to be met with a beet red, flabbergasted gaze- one that was lingering far too much on everywhere. Perhaps she needn't have shifted into jeans that were quite that tight, but they seemed to be doing the trick. She smirked, brushing a lock of red hair out of her face. "Oh Benny," she sang, "something you'd like to tell the class?"

Ben opened his mouth to protest, but all that came out was something halfway between a yelp and a cluck. Lucy burst into giggles. "Oh my muddy armpits! You've got a thing for Gwen!"

"No! Totally don't! You got this all wrong!"

"Yes you do!" She protested, crawling over him, pushing him over to straddle his waist, grinning down at the flustered boy. "Look at you! You're redder than my hair!"

Ben seemed unbothered at being pinned, even if his blush was relentless. "No, totally not the reason! I'm just completely thrown that you would even try to look like her in this conversation of all things-"

"As you humans say: bullcrap! You want to kiss Gwen." She cheered.

"Can you not yell that so loudly?!" He hissed, glancing around. Lucy waved him off, clapping her hands cheerfully. His parents weren't home, so no way was she letting him slow her down.

"But it's true! Right? Right?"

"Absolutely not!" The boy yelped, averting his gaze. Her own turned coy, smirking as she leaned in, closing her eyes for a split second. When she opened them again, he glanced at her, and froze.

She had forgotten the most important bit, it seemed. But then, Gwen's shade of green was very rich and quite hard to pin down without a reference point. But of course, Ben's own eyes were a wonderful reference point in and of themselves.

Blinking languidly, letting her lashes put in some work, she leaned in closer. This time, he seemed transfixed, which was hilarious because while she was hardly a carbon copy, she resembled Gwen closely enough to get the point across and he was totally digging it, if the dilated pupils and shallow breaths were anything to go by.

She bit her bottom lip, pointedly trailing her gaze from his (admittedly gorgeous) eyes down to his lips. "Are you sure you don't want to kiss me, doofus?" She asked, Gwen's voice slipping past her lips in a soft whisper.

His breath hitched and she cheered inwardly. A-ha! Got you on the roleplay, boy! Her private party was quickly derailed by Ben raising his hand to cradle her cheek, looking at her intently-

Oh boy. Maybe it worked a little too well. Then again, knowing what she knew about humans and their weird customs regarding family, and the way Ben would never allow himself to act on what he felt… could she really blame him for reaching out for the closest thing he was ever going to get to kissing Gwen? She was totally being selfless and morally upright here.

Oh don't kid yourself, you just want to kiss him. That you're doing him a favor while at it is just a bonus.

Thanks conscience!

You're welcome.

Inching down, she let her eyes drift shut slowly, enjoying the tickling of his breath on her face and yes so much yes they were doing this-

The doorbell rang and she jumped off him as he fell of the couch, boneless for all intends and purposes. They eyed each other for a long second before he started spluttering.

"I'm sorry, I got carried away because of how you look and it's so not fair to do anything with you when it's only because-"

"I'll get the door, you stay put!" She cut him off, raising both hands to forestall him. "Stay super, super put and hold that thought! We are so finishing this Tennyson." Because she really didn't give two craps if he was thinking about Gwen while kissing her. Honestly, that just made it hotter.

"Err, sure." Ben remarked, seeming taken aback as a he crawled back onto the couch. Lucy gave him a thumbs up, bounding for the door, expecting some door to door salesman, but instead-

"Gwen!" She gushed, jumping forward to glomp the girl enthusiastically, even if she was internally both panicking and cackling. Oh boy, I am either super lucky or super unlucky. Gwen politely returned the hug before pulling back with an eye-roll and a distinctly unimpressed look. It looked sassier on her than on Ben.

"Hello to you too, Lucy. Aren't you looking gorgeous today." She complimented, taking in the Lenopan's chosen form.

Lucy winked, snickering. "I'm not the only one who thinks so." She teased. "You need Ben? He didn't say you were coming."

Gwen sighed. "Of course he forgot… I was gonna help the lame brain salvage his grade average for math. He has a test tomorrow. But if you two are busy..."

...was that a hint of jealousy? Lucy eyed Gwen slyly. "Actually," She mused, deciding that she was very lucky indeed. "I think you came just in time. Ben's not feeling well I think. He keeps turning red, trips over himself... I don't know, it's got me worried. Can you check on him, just to be sure? I'd do it myself, but I have no clue how you humans work."

The slight bit of worry that immediately crept into Gwen's eyes was endearing. "How can you not know? You can literally turn into us!"

"The hell if I know! Better hurry though, he was getting really red."

Gwen wasted no more time, pushing passed her and marching through the hall and into the living room beyond, casually tossing her messenger back to the side. Lucy, for her part, extended her eyes on flexible stilts, like a slug, so she could peek around the corner without being spotted.

Gwen had quickly spotted Ben and, taking in his redness, plopped down beside him to check his temperature. Ben, for his part, was looking at his cousin in what seemed to be something of a daze, pupils huge and face red- as if seeing a mirage in a desert.

Right up until he reached up to place a hand on her cheek and seemed to realize that she was very real and very there and very close.

"You really leaned heavy on the roleplay, didn't you. You look just like her." He mused, voice low. Lucy snickered. Well, 'real' in that he thought 'Gwen' was her, probably trying to get under his skin by mimicking Gwen more accurately.

Gwen, for her part, seemed a bit flustered at his antics. "Doofus…?" She questioned, but made no move to knock his hand aside. "What are you-?"

"You said you wanted to finish this." Ben told her, voice doing the low husky thing again and yummy, that was good stuff. Gwen seemed to think so too, as the Lenopan could see her shudder. That spurred Ben on, as the boy took a fortifying breath. "So let's do this."

He leaned in and kissed her soundly, deeply. Lucy had to bite her fist to not squeal, or do a happy dance when Gwen, after processing what was happening for half a second, eagerly leaned into the touch, sliding into the boy's lap and returning the kiss like she meant it, no holds barred. Oof, can you say 'mutual pining?'

She returned her eyes to their normal state and crept around the corner and into the living room, suppressing a snicker when Ben straight up grabbed Gwen's but, causing a happy sound to tear from the redhead's throat. Not that she could blame him; Lucy did her best when she tried to mimic Gwen, but that ass was a work of flipping art.

Shifting back into her normal blonde self, she moved into Ben's line of sight and waited for him to spot her. When he did, she grinned, giving him two thumbs up. Now for my fun...

He paled and froze completely, not even blinking. Gwen kept going for a moment longer, but upon noticing the lack of response (or signs of life for that matter), pulled back, seeming a bit dazed and bearing the most adorable/hottest blush in the history of human blushing. And yes, Lucy would fight you on that. She followed Ben's line of sight and spotted the blonde girl, freezing herself, eyes darting back and forth between her and Ben, gears churning quickly.

"So that's what you meant be roleplay..." the redhead mused, eyeing Ben. Lucy was impressed, but then, Gwen had always been quick on the uptake, even in hazzardous situations.

Not that she'd qualify kissing their hot cousin as hazzardous. Fun, more like. Sinful, absolutely.

When no reply was forthcoming from the hot cousin in question, Gwen pinched his cheek to get his attention. "You alive there, lame brain?"

This seemed to bring Ben back to Earth. "I'm so sorry I don't know what's wrong with me!" He spluttered, voice rising an octave. "Let's please just pretend this never happened and-" Gwen slapped a hand over his mouth and glared venomously at the boy.

"Look doofus, I've been waiting for this moment for years and I do not need you to Ben it up with your moral crap! So shut up and keep kissing me or so help me I'm going to show you what a black belt in karate can do to a scrotum, got it?!"

Funnily, Ben did not seem cowed at all. Instead, he seemed to get some of his fire back, and in a movement faster than even Gwen could keep up with, he flipped them around and pinned her to the couch, hovering over her face. "Fine then, have it your way." ...okay, the low, husky thing had been great, but the growling-

That was just unfair.

Gwen seemed to think the same, as all she managed before Ben leaned down was a gasp and then it was on. Lucy was pretty sure they had completely forgotten she was there, and was torn between just enjoying the great show and turning into grandpa Max and clearing her throat just to give them a heart attack.

Instead, she decided to give the two some privacy. "By the power vested in me, I declare this hot as hell." She intoned, gleefully. She got a pillow to the face from Ben for her efforts, but he was quickly distracted when Gwen hooked her legs around his waist. Lucy grinned, making a quick getaway.

There were some things she wanted to see in this world, but that wasn't one of them.

A/N: Blame discord for the steaminess. Couldn't resist them dangling a fun plotbunny in front of me. Visualize however you please, be that aged up versions of their OS selves as I tend to do or roll with their Omniverse/UA designs; all work.

EDIT: made some edits so the grammer and spelling is less godawful and added some sentences here and there to make it flow a little better. Plots still the same.