Great idea for a thread Sig. Also definitely put your guide up on the wiki!
Ok this is quite OP.... but still. My top tip is to get a Drow ASAP. Level their magic and specialize as a nympho. You will get 10 mana PER KISS in the 'old' sex menu (It doesn't seem to translate to the "Interaction" sex scenes). Add the sex crazed perk from denying masturbation with an advanced brand and it goes even better. They'll request advanced unlocked scenes (for half the energy cost) again and again until they run out of energy. Which regularly gets 15 mana a pop. You can always cast invigorate a couple of times if they/you get low on energy too.