I'm not sure I would really care for a finger inside my ass. I've never tried it, but I'm not sure I'm comfortable with something going in there. I do, however, really like it when a girl presses on the area between my ass and balls while giving me a HJ. A little massaging there can quickly put me over the edge. It's a specialty that many AMP massage therapists have mastered.
For the record Tits, I'm not at all gay, but I suppose if I were, the pleasurable sensations I have would still be the same.