I've gotta favorite sound when I masturbate. Since I'm uncut, at times my foreskin will make a popping sound as it covers and uncovered my head. Going over and leaving the much wider corona, I suppose causes air to emit this sound.
The first time this happened, I thought, wow, "that's hot" and as it continued it got more and more pleasurable.
The more senses involved, the more turned on I become and sound adds to my stimulation.