The act of slipping someone a note whilst they are making a brown in the toilet.
Often played in the workplace when you notice a colleague enter the toilets. A dangerous game to play if the person behind the door turns out not to be the intended recipient of said note.
Alex: What's Kyle doing following Martin into the toilets like that?
When, at a truck stop glory hole, the giving party gently and loving replaces his or her frontal genitalia with a puckered anus, much to the chagrin of the receiving party.
The naughty, precocious pervert peeked through the glory hole in overeager anticipation of his prize, and was justly rewarded with a brown-eyed Susan.