When you are unsure as to whether or not your fart will be completely solid, and thus you must gently clench your sphincter in attempt to strain out the gas without sharting your pants.
If it wasn't for strainer farts I would have shit my pants so many times today after eating those bean burritos.
The Urban Dictionary Mug
One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.
Buy the mug