My absolute favorite involved the Share (by Fun Factory). With the short end inside of myself, my girlfriend gives the other end a blow job. The visual is incredible and the motion of her mouth and hands moves the share just enough to stimulate my g-spot. It gives me the wonderful feeling of being dominant and as soon as I orgasm, she's able to hop right up and ride me. (=

There's nothing better...

Tough question! I think I'll have to go with her finger fucking me while she sucks on and teases my clit with her tongue.

Finger fucking WOOT!

I find it very hot when I see my girl orgasm because of all the things I am doing to her.

Watching from a guys perspective.

It really depends greatly on my mood. Oral sex is a favorite, especially with fingers inside. Fisting is incredibly intimate and amazing. Strap on sex is brilliant. I don't know if there is any one single most gratifying act.