A collateral effect of having anal sex without a lubricant, which occurs as a red rim around the brown eye. The effect brings associations with the baboons butt. Can be used as a humiliating revenge that leaves itchy memories.
To Baboon someone is to (often with the help of a large-handed accomplice) slap them firmly on the naked buttocks. The victim's posterior rapidly takes on the bright-red appearance of that of the Hamadryas baboon.
Geoff was just picking up his towel when Al and I gave him a run-up Babooning - man, you could fry an egg on those glowing cheeks!