brown kitten-stamp
Also known as a "brown cat-stamp," this phrase refers to when a friend (or enemy) presses a cat's butt-hole on another person's clothes or skin.
Alan was disgusted when Mr. Niersen scooped up his kitten, and pressed her exposed kitten-anus against Alan's skin, leaving a cat-butt smell behind. Mr. Niersen had given Alan a brown kitten-stamp.