Maybe a subject prefers the shape of a cat over that of a horse, or a subject gets off on a specific position faster than the other positions? Adding on to the preferences shown in the first Rack.

Not necesarily ridiculous sized genitalia but still something aroud half the size of a character

A single slave in the facility is singled out and permitted to cum while all the other slaves are in complete orgasm denial. If s/he has been selected previously, the slave begs and pleads to not be chosen again. The chosen slave is fucked by machines, the PC, or someone else, or all of the above until they are sick of orgasms. An alternate choice is to have the denied slaves service the chosen one (PRAISE BE), which would build resentment. If the PC is feeling generous, they can elect to release the pent up slaves to gang-fuck the "lucky" one (re:bukkake). Alternatively, the PC can instead have a marathon of a session with the lucky one in the center of the facility while the others watch. Could go any which way, really. It's all about the haves and have-nots

It may be cool to not let what we gather go to waste, after all

Thrusting into the subject's mouth could be fun!

See below:

Press 2 or 3 during while using the mouth tool to sniff or huff selected body parts.

Pros: Can be used to add buffs to player's cum volume cum spurt strength and frequency, stamina, orgasm duration, reduce refractory duration, and increase subject anticipating.

Cons: Excessive huffing may cause player to pass out from lack of oxygen.

Note: Sniffing is just smelling a body part up close, while huffing is when you cup your hands around it or bury your muzzle in to a body part.

Currently when using the dildo it performs an action but is immediately removed when player interaction ends. This proposes the idea that (like in the first Rack game) where applicable toys/objects/tools could be left 'equipped' to a subject. This would move the object from the toolbar to the test subject's equipment slot (which must be free for the action to be allowed anyway, if I understand how things work currently). If the object is not at a sufficient status to be left, it could return to the player's toolbar as is the case (for example if a dildo was too far out to stay without falling out).

For example, the dildo could be left within a subject at its current depth. Another example would be a 'fleshlight'-like sleeve. Such objects would be able to be equipped from the inventory screen for an NPC or player as well. This would allow for example the player to walk around with an inserted toy/object as currently works for cock rings, but would apply to applicable interaction objects as well.

pingpong balls, stick, food, etc

the Player Characters can be dominated by a subject for a "test".