More or less, yes, thanks for the upvote.

TL;DR: give the ability to have a side quest (possibly with its own test
chamber) to modify the behavior of a subject through mental
conditioning to whatever the player desires, specifically: implanting
them with a particular fetish or having their body react with sexual
arousal (to the point of climax) from certain stimulus that isn't
supposed to be sexual, or is otherwise not something that would arouse
the subject to that extent (such as a straight male receiving anal).
Also make it possible to do the short and fun way in the main lab for
those short on time or who prefer a more hands on methodology.

I figured as much, hence why I included a "too long; didn't read" summary of it at the bottom

yes please.

would love the ability to make a lovely lady climax from exterior stimulation.

I can fap to this, upvoted

I don't know whether to put this in general suggestions or fetishes

I'd be ok with that, actually.

I wasn't aware there was a literal option to turn off fetishes already in the game, though to be fair, I haven't touched the game in a while and probably just don't remember seeing it.

Like I said, if I can turn it off and not have to see it, I wouldn't have a problem with it

and I suppose I should have used a different phrase than "remove all reference to it entirely".

I respect that you have a fetish that you enjoy, but the only way I'd be remotely OK with this being in the game is if I had the option of removing all reference to it entirely.

Bodily waste excrement is a major turn off for most people, and having that be a feature in the game is probably a bad idea, sorry.

more genital variety is good variety

the palm job thingy would be a welcome addition too

living clothes and biosuits could achieve similar effects as the tentacle pits, but would require less work to implement.