See: Jerking off, walking the dog, flogging the
dolphin, whackin' it, spankin' the monkey, wanking off, beatin' the
meat, beat the pud, get your chili whacked, hand job,
masturbate, lubing the shaft, choke the chicken, bash the bishop, slap the salami, stroke the trouser snake, doin' it with Palmala Handerson, Rosie Palms, grow some hair on your hands, lather the lolly, etc.