What do You think are the most important stats for ultimate slut build?
I think we can treat energy as "HP" and endurance as "Defence", so we need to keep healthy balance between those two. I'd say I prioritize endurance.
Mind is also quite important for release desires at the beginning of a combat, but most importantly to use resist orgasm. Now, in my opinion the propper usage of resist orgasm is to wait till your pleasure is around 190% and then stop using it. That way You take energy damege from only one orgasm, while absorbing pleasure for almost 2. If You'd wait for 240% pleasure, or even 290% pleasure, the pleasure/orgasm balance would never be as favourable as at 190%. Since ideally we are taking double the amount of pleasure(endurance) for only one orgasm(energy) I think the endurance is more important.
Stamina I think is not as usefull, plus You will have plenty of stamina from endurance. Investin in stamina regen may be a good idea. Though most of the time You will be spamming "secretary stance" instead of sex skills.
Charm is not really that important as well. You will get it anyway and since in my experience slut builds make the playthrough longer, You will have time to rise it by buying accessories.
Agility is utterly useless and strenght is only needed for anal sex in some cases, so throw those two outside the window.
Dexterity is a riddle. It does increase pleasure damage, but is it less, more or as important as sex skill level?