Imagine Koyori asking (You) to fuck her because she's in heat. She gives you a mysterious liquid, but she tell you to drink it when you're already starting to fucking her. She starts to undress (You), except of your boxers, then she ask (You) to remove all her clothes, except her pink bra and her pantyhose. (You) start to massaging her breasts and then, with your own hands, let her breasts out of her bra. She gets embarrassed, but asks (You) to suck on them. (You) accept, and with your mouth start to play with her nipples, making her more excited. But your senses tells you to start fingering her, so (You) make your way through her pantyhose, pull her black panties aside, and start using your fingers to satisfy her. Koyori starts making lewd noises, and she starts to drip pussy juices. All excited, Koyori tells (You): アノン、それは重要な研究をする時です、あなたのロッドを私の中に入れてください as she spreads her vagina. Seeing what is happening, (You) pull your penis outside your boxers and put it inside her vagina. With her yandere face, she reminds (You) to drink the formula from before. As (You) drink it, the results are immediately visible: your penis grows bigger and thicker, almost twice of your original size. Koyori looks how your penis grew bigger. (You) take her from her legs and start thrusting, feeling Koyori's insides with your penis. After a while, Koyori rises up and pushes (You) to your back, and she takes advantage to ride you while she puts a yandere look, trying to take your milk away. She bounces on your penis softly, and quickly between times, until (You) start feeling that you're about to cum. Seeing this, Koyori replies: 続けて、私の中でそれをしてください。 それは私の研究にとって素晴らしい発見になるでしょう。Motivated by this, you let all your cum inside Koroyi, while she screams of excitement. (You) pull out your penis out of her vagina, and your semen is still coming outside her. Tired, Koyori hugs (You) and kiss you in your lips, cuddle together, and tells you: この重要な研究を手伝ってくれてありがとう。 私の研究室のパートナーになって、このような研究をさらに行うことができます。(You) gladly accepts, hold hands together, and kiss again.