When you have diarrhea and make a sweet stew of gravy, and there is somehow a lone turd floating around exploring the bowl like Christopher Columbus upon the Santa Maria.
After taco bell last night I had a gravyboat the size of a jimmy dean's sausage.
A gravy treat is the combination of felching followed by snowballing; generally this definition applies to two males but can be used to refer to any sex.
Did you get in on the Gravy Treat action at the last swinger'sparty?