Eat a Mars Bar

Clenching and unclenching your buttcheeks as if there was a Mars Bar jammed inbetween them. This is to ensure you keep the blood flowing when standing still for a long period of time.

Instructor: To keep the blood flowing don't forget to eat a Mars Bar. Don't fully eat a Mars Bar, and don't produce a Mars Bar.

wuzzis

An abbreviation of "what is this" or "what's this"; used when you're too lazy to write or say the phrases mentioned

Father: Wuzzis sonny boy?
sonny boy: what?