Interact with test subjects/possible lab partners on them!

Training a subject, like say a male who isn't interested in other males into becoming sexually attracted to males and other such fetish trainings.

Add a public toilet somewhere close to the locker room and shower, allow the player to masturbate in the stall, cum in the urinal, have fun with the NPCs in it, etc. Or just let the player relief itself normally (Not scat or water sports).

the head says it all, you inject something in the subject's testes, or let something loose on the(like a goo monster)onto the subject, and alters their testes, till they produce someone elses sperm, or a new substance entirelly.

Test Subjects that you can sex without having machines holding them, the players can fuck them in a few different positions (ex: bent over, standing, agaisnt wall, etc.) and the Test Subjects can also fuck the player as well if they have a penis.

Wether it's the player fucking the Test Subject or the Test Subject fucking the player, both ways could count with the same positions.