When one lays some gas and proceeds to catch it with their hands making a fist and then use it for another purpose, often a practical joke for the poor smell.
John "That sewage downstairs smells so bad!"
Bruce "Yeah, I know, when the elevator comes up it is cupcaking the whole buildinge"
The art of ensuring that your fart is smelt by your victim, and possibly even breathed in.
Basically you cook up a real stinker in your colon, CUP your hands over your "exit-hole", let loose taking care not to 'spill' the contents, and waft/push/throw into your victims face so they get the full 'benefit'.
Then casually remind them that fart is made up of minute microscopic poo-particles and they have in fact, 'just eaten your shit'.
Jed sneaked up on Gaz, with a real devestator lodged in his bowel. Discretely he moved his hands to his arse, farted whilst simultaneously cupping then unleashed his stink on Gaz'z person, Cupcaking him.