Unlike a turtle head a 'slumbering turtle' is knowing that you have a poop coming on, but it is not yet as severe.
I've got a slumbering turtle right now, but I might want to get it out before it turns into a turtle head!
A poop that hasn't or won't come out, before it becomes a turtle head.
Keep your fingers out of the booty, there might be a slumbering turtle! #Kanye
A poop that isn't ready to come out, or won't come out. The state of a poop before peaking and becoming a "turtle head".
Please, don't put your fingers in my booty. I have a slumbering turtle. #Kanye