Tunneled buttplugs that allow penetration, free flow of fluids and  keeps holes open.

Just writing and text on the body. Could be for humiliation, or just tallying up how many times the subject has been used/orgasms.

I haven't seen this anywhere, and having had the idea I don't want to risk forgetting it. So I'm talking stuff like this https://e621.net/post/show/897540/2016-anthro-anus-belly_scales-bent_over-big_butt-b But maybe you could have the option to crank it up or down, and change the color. Maybe there could be a species, or it is just a rare thing that anyone could have. You could take the dna, enabling you to put it in other subjects. Perhaps their cum/fem cum could glow as well. Making the colors match could be optional, allowing the player to have any combination of them. As an offshoot, perhaps it could affect lactation. Affecting color and possibly flavor for both.

Not just genitalia portals, but large ones so you can have for example half a character (butt) coming thugh the wall while he other half (torso) is on the same side

Since it looks like Rack is getting an update to fluid physics, why not add more fluids to the game?

The hymen is a membrane found at the outer opening of the vagina, and is typically torn by careless lovers, emitting mild amounts of blood.

I hadn't seen this yet, so I figured I'd type it up myself, since this is a science game after all.

what I had in mind was to have a device that would scan a subject and map out their nerve endings and analyze their pain/pleasure senses and sensitivity, erogenous zones, etc. It'd offer the option to enhance or decrease sensitivity, as well as directly or indirectly stimulate the nerves to produce desired effects (instant orgasmic pleasure for instance)

I had two ideas for how this would function, direct, indirect and maybe a hybrid of the two.

indirect mapper (easier to animate): the scientist has a scanning device that projects a beam over the subject and maps out their nerves by applying stimuli to them. After the mapping, the scientist can then use the beams to manually stimulate nerve clusters as they desire, able to pinpoint specific nerve clusters (tip of the penis or clitoris for example) and activate the pleasure receptors in that specific area via the scanner beams.

Direct mapper (harder to animate): a more complex machine that has a set of arms with ball point pads at the ends of its "fingers" that run over the subject and scan the nerve clusters through stimulating them and taking readings of the subject's response to various stimuli. The scientist could then use the arms and "fingers" to manually apply various stimuli as desired (electrical, vibration, direct nerve stimulus, etc) just like with the indirect mapper.

Hybrid: a mixture of the indirect mapper and direct mapper, any combination of the two.

overall, the procedure should be able to be particularly intense, opportunities for potentially crazy overstimulation and pain all around.