"Laughing My Ass Loose"
For when something isn't funny enough to "Laugh Your Ass Off", but in the glorious estuary of laughing it loose.
Person 1: Omg, comedian is so funny, lmao
Person 2: I don't think that comedian is that funny to laugh your ass off over.
Person 1: What would you say then?
Person 2: Lmal- Laughing my ass loose.