To touch, twist or simply rub the left or right nipple.
Nippling is a common act that is done mostly in Perth, Western Australia, namely the horny boys that go to Chisholm Catholic College. Nippling was first created when two boys decided to touch themselves in odd places in a physics classroom. The nipple became the chosen destination and the rest is history
boy 1: wat the fark are u doing boy 2??
boy 2: its called nippling!!!
boy 1: ohh that looks niiice. Mind if i try???
(it is beleived that these two boys became homosexual after these events that took place)