What do ants use when they're stinky?
Deodorant.
Okay, so like, ants are tiny, right? And deodorant makes you not stinky. So, the joke is that ants use deodorant 'cause they're stinky. It's funny 'cause ants don't actually use deodorant. And neither do you, probably, you unwashed swine. But hey, you get the joke now, don't ya?