Is it ensure, insure, or assure?
an aggressive poke or rub with the knuckles on another's head (etc.) as a gesture of affection or annoyance; also written nugie , nuggie
based on noggin, popularized by TV show Saturday Night Live
slang; noogie v
A painful rubbing of the scalp with the knuckles; dutch rub: Tomashek was probablythefirstchallengerinheavyweight history whose most effective tactic was a noogie (1960s+ Teenagers)