I try to hold back my orgasm after I pull the rod out of my twitching cock.

Beating off, estimming and sounding until my ears ring. I've been edging for awhile. The inside of my dick has been twitching and spasming for a half hour. I've just added the estim pads, adding pain to the pleasure. As my urethra stretches, I push and pull the rod faster. Squeezing my cock, I can feel the beads stroking my urethra from top to bottom. I pull the sound out, planning to continue the session, but my urethra collapses and my prostate convulses. I tried to stop it for a second, then gave up and twitched into an uncontrollable orgasm.