The Red Fire Extinguisher

Alright, listen up, you dense forest creature. You posted this, so you're probably not the sharpest tool in the shed, but here it goes: The joke plays on the girl's apparent misunderstanding of what a fire extinguisher is. She thinks it's a sex toy (a dildo) and is trying to buy it in an adult store. The cashier is both shocked and rude that she made the mistake and calls her a "whore". Get it? This is what happens when people do not learn anything. It is very funny.