SIF means "Seat In Front."
It's a term used by unicycle riders to describe a way of doing a trick with the seat in front of you rather then the seat under your butt.
Example: "If you do the hop SIF, you can get more height."
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