The bead of sweat that rolls down your Sister's back when you're banging her doggie style.

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."

The sweat that drips off your balls when you're caught fucking your cousin!

It's that little drop of sweat that beads up on the back of your neck and dribbles down your back, thru your crack and eventually drips off of your ball while your fucking you sister.

the sweat on your balls while fucking your cousin

the saliva left on your genitals after your cousin gives you oral sex

The perspiration that forms between the shoulder blades of your first cousin, while you are fucking her in the ass.