This story is going to be pure smut. Also. I published this on Ao3 last year.

Marco was sweating bullets. He had been dating Jackie for almost a year now and what he was about to tell her may destroy their relationship. Star was behind him, looking uncomfortable. She didn't want to be a hindrance to their relationship, and now they might break up because of her.

They were sitting down in his bed in front of Jackie.

"So, what's up with you guys? You look like you're about to tell me my cat died or something. Because you two look like you just saw a tragedy"

"Jackie, you know I love you–"

"Yeah, dude, I know. You've told me like a thousand times already."

"A thousand and thirty three actually. But, please let me finish. You know I love you, Jackie. So please, don't break up with me after saying this. I'm saying this because I can't stand feeling like I'm be–" he winced when Star pressed down his hand a bit too hard. She hid her face behind his back. "Okay, I'll get to the point."

"What are you talking about?" said Jackie, her smile becoming strained. They were starting to weird her out.

"I called you here to tell you that I been having sex with Star."

"...What?," she said quietly as the smile dropped from her face, quickly turning into a frown.

"Please don't think that–"

"Are you two for real?" She almost screams from her seat. After a minute without answer she looks at Marco and asks "Is it because of… That?"

"No it's because–"

"He's been trying to help me." said Star from behind Marco, finally looking at Jackie."

"Of course he has," said Jackie with biting, angry sarcasm.

"I swear it's not like that. Look, I know it's hard to believe right now, but Star isn't exactly human."

Before Jackie could interject, Star moved fully into view and struggled as she grew two new pairs of arms out of her sides, her skin slowly turning into a dark shade of purple.

"They go this sort of monthly heat. I saw it once, before we started dating, and it's not pretty," Marco said sheepishly.

Jackie looked at him with her arms crossed. Even with all of the insane stuff they had been through lately, this whole "needing to mate" thing was hard to believe. If a purple cephalopod Star wasn't sitting just beside him, she wouldn't have believed him. "If they lack a mate for a while, they kinda sorta go berserk and kidnap males, to…you know. Unwillingly."

"I did it once," Star said, trying to get back into the conversation but still fearing Jackie's wrath. "I webbed everyone in school and I almost…" she trailed off, tears starting to roll down her cheeks. Marco hugged her close.

"Then why don't you just masturbate?" asked Jackie, looking with at Star like a boyfriend stealing hussy.

"They need an exchange of genetic material." Jackie raised an eyebrow.

"They don't need to be fertilized. Normally just the smell of… it, is enough to calm her down. That why I used to just, you know... let it out on her face, but one thing led to another...and now we do it once a month to prevent her from going all 'Species' on every guy in school."

Jackie's eyebrows shot up as she realized that beautiful, innocent, baby faced Star Butterfly apparently liked to take cumshots to the face. But the fact that the guy shooting those loads was her boyfriend was upsetting.

"I see…" Jackie said, sadly.

She got up from her seat and announced that she was going home

Were they still a thing? That's up in the air.

For the next few days things were uncertain. Jackie made no attempts to contact Marco, even ignoring him at school. And that worried and depressed him. She wasn't angry. Just insecure. She didn't want to admit it, but Jackie and Marco have been having sexual problems ever since they started "experimenting." She has never been able to "take him". She was afraid of trying to "take him." He was 6 inches long and two inches wide which was very big for a boy his age.

But the problem wasn't him, it was her. She is too small for him, and for everything bigger than her own fingers. And that bothers her, she could never please a man because of the great pain that it caused her to try to take a dick in. Which in term, meant she could never actually please herself that much

"But Star's fucking him just fine," Jackie thought.

After school and almost a week after the reveal,"Jackie went home, dropped her backpack, and threw herself on her bed and thought about them. Her beautiful, hard working, always trying, kind-yet-a-bit-awkward boyfriend, and that deceiving, cheating, boyfriend-stealing, probably oxygenated blond from another dimension were probably doing it right now, behind her back.

She didn't know why, but that made her feel weird.

Not angry or even apprehensive, just very strange. He was one of the best boyfriends she ever had, Whatever she needed, he did, and just because she asked. When time came to get in bed, he was the only one who actually stayed with her after the 'you don't get it, I can't physically do it'.

I don't deserve him.

He probably knew that, that's probably why he does it with her, he probably got tired of waiting and trying and moved on to somebody new.

A tear went down Jackie's cheek. She started to imagine them in bed. Star had that look that only a woman that knows how to truly pleasure a man can give. She was looking at Marco's naked, toned body, when he got closer. Star caressed his hot, brown skin. Just looking at Star's naked body gave him a raging erection. Jackie could picture every single vein on his dick and Star's pussy glistening with her fluids. She could see how much they wanted each other.

Jackie took off her pants with one hand, her other hand busy caressing her sex. She saw it in slow motion, Marco's huge, wonderful dick going between Star's folds, tearing open her cunt with his sheer size. She can hear Star's moans, her loudness only dwarfed by her immense pleasure. With her eyes closed, both of Jackie's hands picked up the pace, one played with her clit the other one caressed one of her breast.

She saw Star whisper something in Marco's ear. He responds with a smile and a kiss. He then pushed his dick inside her with the sheer strength and savagery of a wild horse.

Jackie's own pussy got wetter and wetter with every single push. Her mind's Star got used to Marco hitting her cervix every time he goes in and claws at his back when gives that one final push, driving her over the edge. Jackie could see it, his member pulsating, shooting all that potent, fertile sperm inside Star's womb. Every single one of his throbs made Jackie closer and closer to her own climax

Then she saw it. Star's confident, smug expression, her eyes telling Jackie "Yes, I just took all of your boyfriend's cum. What are you going to do about it? You stupid, frigid, Barren, VIRGIN!"

Jackie's back arched, her eyes rolling back, and then…she let it out.

"Did I...did I just pee myself?" No, but she was going to need to wash the sheets regardless. "I...I just…squirted. I don't think I've ever done that before."

A little known fact about Jackie Lynn Thomas was that she masturbated. A lot. Above learning about dead cultures and below skating, masturbating was her favorite activity. She dedicated herself to doing it several times a day. Her recess time at school. A few minutes after studying in her room. In the bathroom while thinking about the Roman Emperors. In her church's bathroom during the sermon. But she had never, ever, squirted before. This was like pushing away all of her frustrations, her insecurities, her boundaries. Everything in a huge, cunt shattering orgasm. And it was like

"wow"

It was all she could think about. Her mind was almost blank as she looked at the ceiling. "who says you could find new things about yourself while masturbating?" she thought.

In a sudden hurry she opened her drawer, looking for her phone.

"I need to call them."