The act of rimming someone when they have your head locked between their thighs.
My girlfriend wouldn't rim me so i tried a warm turtle.
When something is so awkward/horrifying you pull your shirt, jacket or sweatshirt to cover your face. Normally this contains/disguises your laughing fit.
Someone looked up what truffle butter was, I full turtled for 5 min.
When a bitch is taking a literal shit and you ram your cock up her ass.
Damn dog you made that "turtle retreat"