The very pedestrian cock in the mouth and cock in the vagina is always a winner for me. Whether I'm on hands and knees getting it doggy style, or sitting on a cock and sucking the other, or sucking on both when in 69 with one of the guys and the other is next to him ....
I guess, though, the absolute favorite is me on all fours, getting it doggy style. The guys can switch ends real fast and keep me going for a long time.