I have been reading this site for a while now and I am suppressed I haven't seen this technique yet, or maybe we're just weird.
Every once in a while I dig out this thong swimsuit my wife bought just for this purpose on our honeymoon. I simply draw a warm bath and read a story or some times she gives me a show to get me in the mood. Once I have a full erection I pore some conditioner in the front of my thong and either my wife or myself will start rubbing my penis through the suit.
As the rubbing continues the conditioner works its way through out the thong acting as a lube. The feeling of the slippery material rubbing all my sensitive parts at with the motion of the hand gives a mind-blowing orgasm.