Ona a Saturday afternoon, buried under the mountains of books and notes, Phineas and Isabella were preparing for the upcoming chemistry test. Isabella wasn't sure why Phineas invited her to help him, but she cherished every moment she could spend with her boyfriend, and if everything went smooth, she could easily stretch the revision from Saturday to Sunday as well. They took turns, asking each other a series of questions, breaking every once in a while to chatter about something more important than school. About a year ago Phineas finally understood his feelings for her, and now, after a glorious Summer they spent together, going back to school felt like going to a prison.

Isabella grabbed her cards, and was about to start her round of questions, before an idea came to her head. A dangerous one, but one that could change the afternoon from good to great in mere minutes.

- Let's do something different, though... - she smiled friskily - How about this: for every bad answer, we'll have to take off an item of our clothing.

- What?! - Phineas shouted, taken aback by her proposition - Isa, Isabella, that is...

- Oh, what? It's just a game. I;m sure you will be fine...

Isabella smiled, and begun reading.

Twenty correctly answered questions later, her smile washed off her face.

- Okay, now it's your turn, I guess.

She handed him the questions despondently, and leaned back against the pillow, murmuring something under her nose.

- Heh, yeah, I guess I was lucky that I knew all the answers - he chuckled, trying to hide his fluster - Okay, so... "A common product of acid-base neutralisation reactions is...?"

- A butter - Isabella answered, staring Phineas straight into his eyes, still haiving her arms crossed

He blinked.

- Uh, no, Isabella - his face frowned - I mean, it cannot be "butter", the correct answer is-

- Oh, gee, I'm such a clod. - she said loudly, and took her shirt off in one, swift move.

Underneath it, Isabella wore an intricate, pink bra, a piece of clothing Phineas so far could only dream about, and only if he allowed his dreams to be that wild.

- Uh, I-Isa, I... - he stammered, trying to look away

- Keep reading, that;s the rules of the game. - Isabella fluttered her eyelids, looking at him in a mesmerising way that nearly rooted him into the ground. And suddenly, he felt obliged to read, even though he knew what would happen next.

- Uh, let's see... "Wh-What is the oxidation of an o-o-oxide ion?"

- Hmm... - Isabella playfully put her finger in her mouth, put it up in the air, and let out a fake sigh - I'd say... North, North-West.

- No, it, uh, it can be "plus" or "minus", and it's...

- Oops, guess I didn't study hard enough.

Phineas gulped down the sudden collection of saliva that appeared in his mouth, watching Isabella unhooking her bra. A moment later Isabella revealed, quite nonchalantly, her modest breasts, which made Phineas almost completely close his eyes. Almost, as the image of her naked torso was too tempting even for him, and it has already burned in his mind.

- Listen, uh... I, I'm fairly sure, even though I've never played strip poker... - he quickly added, hiding his face in hands - That you are supposed to start with the... the, uh outermost layers.

Phineas bit his tongue, as he suddenly understood that he encouraged her to continue removing clothes, in his room, and that his mom could enter it at any moment. As Phineas babbled, trying to correct his statement, Isabella hasn't moved a bit, and stared at him with flirtatious grin, observing how he had to restrain his pupils from looking at her breasts. At some point, he couldn't pretend anymore, and lowered his hands, taking one deep breath after another, marvelling at the sight og her bosom in front of him.

- Oh, really? - she asked, faking surprise - Well, look at that... Old, silly me. I guess that counts as a wrong answer as well.

Phineas's first thought was to protest this debauchery, and next that Isabella wanted to kick him in the face, when her legs soared above the bed. But then, his eyes went wide when he saw, for the first time in his life her matching pink panties with distinctively darker wet spot in the middle, being slid down her legs, up to his face.

- I-Isabella...

The panties joined the pile of Isabella's clothing on the floor, exposing her meticulously groomed, glistening pussy waiting at the end of the corridor of her short skirt. Now, there was no force in the universe that could make Phineas turn away and not gauge at her sex - at least, not until Isabella straddled him. In one move, Isabella rose to her knees and climbed to his laps, peppering his face generously with kisses. The same enticing, enthralling, wet place Phineas was staring at, now hovered just above his crotch, and from the feel of it, Isabella was heavily enjoying it.

- One more question, Phineas. That skirt isn't gonna take itself off.

- Uhh... - Phineas paused, feeling paralysed by the naked figure sitting in his crotch. He was sure he just felt something wet tracing his erection, which caused him nearly to leap in place, though her weight has prevented him from doing it.

- Come on, I need to lose properly.

- Uh... "Which element has 16 neutrons, 15 protons and 15 electrons?"

- I don't know, a platypus? - she "answered" sharply

- Er, wrong.

- Finally...

From his laps, Isabella leaned onto her back again, lifting her legs high in the air in a stunning acrobatic move, exposing Phineas to the tantalizing smell and sight of her pussy once more. The skirt flew to the ground, as Isabella snatched the cards from Phineas' hand.

- Now it's my turn. - she stated, pushing her boyfriend to the bed.

His figure felt featherweight, as if all of the energy in his body were used to process the mesmerising strip-tease of hers, and that with enough practice, she could wind him around her finger.

- "Which laboratory technique is best to separate a solid from a liquid to recover a liquid?"

Liquid. Phineas stared at the drop of a clear, viscous liquid that spilled from her pussy, staining his bedsheets. That must have been the source of the smell that drove him mad a moment ago, he thought.

- Uh...

- Wrong!

Still gaping at her sex, Phineas threw his socks off.

- "Which of these values is most responsible for changing the boiling and freezing points of a solvent?"

Boiling. Something was boiling in his chest, so much so, he started undoing his shirt a moment before Isabella commented his lack of response.

- Wrong again!

Phineas took his shirt off, giving Isabella a quick peck in between. She was equally ravenous as he was, but they both felt they have to finish the quiz, perhaps just to leap into each other arms with more ferocity.

- "The physical process of evaporation involves..."

- A cactus - Phineas replied, before Isabella begun reading possible answers.

- Good. I mean, wrong, but nice that you finally joined me.

His cargo pants evaporated to the ground, showing his boxers that couldn't hide his erection anymore. Now Isabella had trouble breathing, while her eyes darted to his crotch every few seconds.

- "Increasing the volume of a sealed container will cause the gas particles within the container to..."

- Explode. - Phineas replied, sliding down his pants.

For a moment, Isabella though that this very process will happen, quite prematurely, once he said the name, in a stern, almost dominant voice. But his long shaft simply twitched into position, once Phineas slid his boxers. His head was red, glistening, and most importantly, inviting.

- Oh, you are wrong, so... Very, very wrong...

Isabella chanted, while she closed her hand around his shaft, giving it a delicate pump, observing as Phineas' face twists in a grimace she hasn't seen so far.

- One last question... Do you have a condom?

Neither of them noticed that, but the Sun slowly begun to set, and Isabella looked at Phineas' naked body not in the light of day, but in the enticing, romantic, orange glow of the afternoon, one of the few sunny September ones left. His hands pulled her body towards his, and for a glorious split of a second, his tip brushed her opening, causing her voice to quiver.

- If I answer correctly, do I have to put on something this time?

- Oh, yes - Isabella moaned, suddenly feeling she's losing control of the situation she crafted.

- Then yes, I do.

In one move, he toppled Isabella to his bed, covering her mouth with his. For one, horror-filled moment, Isabella thought that he lied, and was about to enter her without protection, but then she saw his arm opening his nightstand's drawer, and understood that making them fall was the easiest way to extend his reach.

- Let me...

Isabella took the package from the quivering hands of her boyfriend, ripped it with her teeth, and slid the condom down his warm, throbbing length. Once again, she let him touch her lower lips and her clit, and even though the texture of rubber didn't feel as good as his wet, hot skin, it still was an electrifying experience. Isabella closed her arms around his body, that Phineas supported gallantly on his elbows, a few inches above her breasts, let out a deep moan, and spread her legs, awaiting the intrusion she's been waiting for for years.

- Isa... Isabella? - he suddenly asked, breaking the tranquillity of this magical moment - What...What if I do something wrong?

She opened her eyes, and gave him a long, soothing kiss that calmed his trembling arms.

- Take your time, Phineas - Isabella whispered - There are no wrong answers here...