You're

You're jokes

Your mama is so stupid that she put a ruler under her pillow to see how long she slept.

Timmy: Stupid motherfucker.

Jimmy: Wow, do you kiss your mother with that mouth?

Timmy: *starts crying*

Jimmy: Ah fuck, I did it again.

Orphan: Wanna have a sleepover?

Friend: But you're an orphan.

Orphan: Just wanted a place to sleep tonight!

Your sister is so stupid, she only thinks an onion will make people cry.

So I threw a coconut at her.

You and your sister always get into a fight and she says, "I don't care." Then you say right away, "About you!"