Cum should leak or even spray out from the stretched walls of a stuffed vagina (tail hole as well?) when it's filled to capacity with cum + cock. Perhaps a displacement of fluids effect due to phallic object entering a hole and pushing the fluids out. (It all has to go somewhere right?!)

If impregnation does get in, then myself would like it to be a fairly big deal. Breeding certain traits, physical or mental, having the PC mate with whomever and be able to knock them up/ be knocked up. And Have it focus on the pregnancy, swelling belly, lactation, peeing more and perhaps strange cravings. Then, after the offspring is born, you can make it grow up quickly somehow, and afterwards, mate it with its mother and or father, to then knock them back up, or be impregnated. Maybe depending on the subject, they could be really against it and you have to force it, or they could be excited by it. And some nice breastfeeding, incestuous or no, would be fantastic. Lactation over all would be great. Naturally or artificially inducing it. However, have an option somewhere that enables hyper lactation with small breasts. Because me, myself and I, vastly prefer little mounds to big boobies. And that's a very sexy thing, getting a lottt of milk from a little tank. To me it is anyway. And of course, this would all be for herms as well. Now, solo watersports, not everyone likes them, and that's fine. But me, I would loovvvve being able to have female/herm subjects pee themselves. Really detailed, watching the urine flow down their fur, soaking whatever it comes into contact with. And making them hold it would also be a big part.

Cock milking machine, with various speed settings and suction strengths. Variations can include one that strokes up and down, or like a cow milker that handles all stimulation internally, and just stays flush with the body.

The character (female/male etc.) could orally satisfy themselves

Since it is possible to vote on sharks, I think it would be a good idea to vote on, if people want the inclusion of hemi-penis. Though the bigger question is, if that is actually doable with fek having to create a entirely new skeleton from scratch.

Whether it be actual laying, or just stuffing egg-like objects into (and back out of) orifaces.

let us use a subject's dick on themselves, other subjects, or even just display them on a wall

Fairly self-explanatory, I'd love to see kissing in this.