What do i do if my sister is being super annoying and i just want to slap her across the face?

There's a little something called patience. It's really good. And there's also forgiveness. 你 should try both

same story as u.

I usually imagine it.

Try ignoring her, that might make it seem like 你 don't really care.

instead of wanting to slap your sister take your agression out on your pillow,or one of those clown blowup 玩偶 或者 a punching bag

First 你 need to calm down and ignore her. Tell her to stop being annoying if 你 can. Don't resort to hitting her to stop her from being annoying. You'll get in trouble and she'll probably not like 你 anymore.

Slap her 或者 ignore.
My bro is the same.

Slap her. Suffer the consequences.