Capping a fart
Capping a fart is the process of capturing your own fart gasses in your sealed, cupped hands. Usually followed by throwing it into the face of someone nearby.
I had had it with Jim's coy retorts, and barbed comebacks. The moment we sat down at the french restaurant, I hiked my skirt up under the table, reached down with both hands - carefully capping a fart to throw at him.