Me: Hey you trashy pig woman, go in the toilet or lay on the grass where you belong.
Trashy pig woman: Why?
Me: Because you smell like fart and you're pretty much just a turd with lips.
Listen up, buttercup. This joke is about a person insulting another person by comparing them to trash, a pig, and a turd. The joke is that the insult is super harsh and over-the-top. You are not smart if you don't get it.