Galloper
A galloper is when you laugh so hard you can't breathe. It's like when your friend tells the worst joke ever and you're cackling like a maniac.
He told a joke and I was a full-blown galloper. I had to sit down.
She was laughing so hard, she turned into a galloper. I joined her.
They told a joke and we both turned into gallopers. The whole room was laughing.