I love anything where the women are enjoying themselves. It doesn't matter so much exactly *what* they're doing - but if they're enjoying it, it is so much better. A genuine smile makes all the difference. And if they have an orgasm - well that is such a turn on. Can't stand the fake moaning - but a genuine orgasm is wonderful - even if it's very quiet!
My big fantasy is wife-sharing group sex, be it threesomes, foursomes, etc. and if there is some bi sex in there of any type, that's even better. MMF, FFM, FFMM,