The ‘climax’ of the experiment.

A small burp escapes Rachel’s lips, but nothing incredibly happens immediately. “Oh, did I not mention? I need to be made to cum now, just like any other victim of Lilith’s embrace. I know you’ve both been wanting to do it for ages, but not as long as I have. Fuck me demons. Fuck me so I can become one of you!” As she says this she leaps into your arms.

Needing no further invitation, you toss her onto the bed in front of you and spread her legs. Becky hops over her face and lowers herself onto Rachel’s mouth as you push your way into her cunt. Rachel’s groans of pleasure reach you even through her mouthful of demon pussy. While you hump her willing body, Becky leans down and starts to lick Rachel’s clit with her lithe, forked tongue.

As you gaze down on the two ladies before you - one human, one demon - you get the impression that Rachel is inexperienced in homosexual lovemaking, but what she lacks in quality she sure makes up for in enthusiasm. Becky soon climaxes on her face, rolling off the bed and collapsing on the floor, shuddering erotically, and that fact triggers your own orgasm. You shoot deep into Rachel’s pussy and simply keep going, ploughing away in your bid to bring your willing victim to her own, final peak.

Rachel soon begins to evince the natural discomfort that comes with the inability to reach orgasm pre-required to ascend to demonhood. She pants and moans, pushing back against you with your every thrust. “Why... can’t... I cum?” she cries, desperately.

“You will soon, my dear,” you reply. “Very soon. Your transformation is imminent, I promise.” Even as you say this, a red hue begins to creep over the sexy student’s skin and her eyes narrow to slits. Pounding hard, you watch as her blemishes and surgical scars vanish from the now deep crimson surface of her body. Her breasts swell, bra snapping and falling away. Ears point upwards, nails grow into claws and her pubic hair withers beneath your thrusting. Her hair lengthens, but instead of darkening to the shade of your own, it lightens from its natural blonde into a pure white, purer even than artificial bleaching ever obtained. It does nothing to diminish the sexiness of her new, emerging demonic form, and you feel yourself swelling inside her again as another orgasm builds within you.

“Yes! Oh fuck yes! I can feel it. I can feel the power!” Rachel screams, tail, horns and wings bursting from her flesh even as you continue to ram yourself into her. With that, the two of you both cum. You feel her soul seep into you, empowering you in a way different to the way Becky did, but just as delicious to your devilish hunger.

Rising from the bed, basking in her newfound demon glory, Rachel stretches her wings as much as she can in the cramped space of her bedroom. They are a silvery grey, unlike the matt black of yours and Becky’s, as are her talons and claws. But, as with the hair, these differences do not seem to matter to her erotic nature, in fact, the reverse. You can feel power emanating from her, power greater than your own. It seems you have created a superior Mistress for yourself, and you cannot decide if you like that idea or not. Jess may have sired you, but you were always the leader in that relationship.

“Mmm...” Rachel murmurs, her attention returning to the room around her. “That was... exquisite. A much greater gratification than I had predicted. Thank you both for providing me with my release. I feel the urge... to feed... and to test my skills, of course. Will you join me?” This question is directed at you, Becky being your pet. “Want to see what I can do?”