The most mundane thing is a pair of clippers on the back of my head while I'm getting a haircut. It's why I don't like dudes cutting my hair; feels weird. The other is a woman speaking softly in my ear. That elicits a much... [i]stronger[/i] sensation. (I'm not talking headphones or phone calls or anything. Gotta feel the breath, feel the proximity, feel the reverberation of her voice through her body essentially.) I could probably utilize that second one in a non-sexual manner, but the circumstances for fulfillment make that slightly difficult. Besides, achieving orgasm while having that tingle across my head and upper body feels pretty damn awesome.