Rolfmayo is a derivation of the Internet slang roflmao (rolling on floor laughing my ass/arse off). It basically means the same thing, but features far more Rolf and Mayo.
Particularly popular in England, rolfmayo is an indirect reference to both the celebrated Australian painter and entertainer, Rolf Harris, and the equally enchorial salad dressing, mayonnaise.
I just saw an old lady fall over! ROLFMAYO