whack off

verb

1. To masturbate.

   “Did I mention that when I was fifteen I took it out of my pants and whacked off on the 107 bus from New York?”

   “[…] why is it that I am discomfited by the bizarre fact that the one thing she will do, though in a pleasureless and rather perfunctory way, is to whack me off hour after hour until I am a lifeless and juiceless stalk, exhausted and even humiliated by this dumb pursuit?”