1. The act of insulting someone via a reference to an embarrassing event in their past. The term was popularized by a scene in "Goodfellas" in which Billy Batts admonishes Tommy DeVito for his subservient childhood job by exclaiming "go home and get your f**kin shinebox."
2. Attacking someone for previous shameful actions, giving the impression said acts are indelible.

The act of extreme masturbation. You must "knock one out" whilst in close proximity to any of the following; Your mum, a nun, your boss, a member of parliament, George Michael. A person with capabilities to act upon catching you mid self-abuse obvisouly ups the ante. Ejaculation must be reached before your danger wank target comes (no pun intended) to investigate. The higher the chances of being discovered with one's pants down, pulling one's war face is obviously where the danger comes from. The more danger involved the harder (or softer) it is to complete the task in hand (snigger). The more dangerous the better. The chance of being arrested, pummeled by an angry father or having your hand severed by an arab's sabre means that you are a pro "Danger wanker."

A way of saying you knew somebody back when they pissed their bed, kind of like they knew you back when whined to your mother or father about getting somebody kicking the shit out of you.