It's when you stick a finger in the rectum of another person and then jerk him off with the other

It involves four condoms, a ballpoint pen and a sink plunger: you can work out the rest from there.

When a girl pleasures a man in the big spoon position with her legs wrapped around his body, like a Koala bear on a tree.

To suck dick from behind and take nut in your grill.

More genteel than the normal meaning of "reach-around", a Norfolk Reach-Around refers to the act of passionately grabbing a partner's bottom during the act of snogging.

When one is at a urinal taking a piss and someone comes up from behind you and cuts off your penis

When you're having intercourse in a doggy style position or any position from behind and you reach around and sock them in the face a few times when they aren't expecting it. Much like the hockey players checking each other against the glass and getting a few punches in when the refs aren't looking.