The Dirty Liam is when you get a hard on in public by looking or doing the simplest thing e.g hand holding or looking at a woman.

Sitting on the crapper doing the business while the bitch is polishing you off, whilst 10 other hot chicks chant your name outside the toilet door.

Jerking off a ginger friend while he’s playing ark survival evolved on the map schorched earth trying to do ultimate ark while killing thyla S