Is there truly a way to get your pets to fuck you?
Yes there is try getting the wolves in the forest to like you to the point that when you encounter them there's a different message and the choices are accept your position and defend yourself after accepting your position when you get a pet in the training menu should be the option to teach them to mount you. (If that doesn't work like that I'm sorry, it's just that in my training menu the option is always there so I think that's how it works since I always do that)
So you have a positive reputation with the wolves for sure, how much have you fed the pets? You can keep feeding them to 26 likes, and some of the skills don't unlock until you have fed them enough/gotten enough likes. Not sure which since I always just feed them til they stop "liking" it and all the skills are unlocked for training.
Clarification: you can feed them even if they are at 100%, force feed them basically. It has never caused any problems for me and it does unlock skills for training. It's almost certainly the likes since the are 100% energy long before the likes stop increasing at 26.
You can also increase likes by naming the pets again and again, same name is fine, you can get to the max (50 likes) doing this, again it has never caused me any problems.