Means that something is awesome and/or amazing. Etymology: This term was derived from "Sweet Mullet" in an attempt to translate "sweet mullet" into Spanish by way of "Dulce Muleta." However, mullet has no Spanish translation, and "muleta" actually means crutches in Spanish. Hence the term Sweet Crutches.
Rob: Dude! I made out with Ethan's sister!
Rick: Haha! Sweet Crutches!
Ethan: You did what?