A big tough shit. One that you really have to use your anal muscles to push out after eating a big meal the night before. And it hurts like hell when you push it out. It is sort of like a variation of constipation.
This is one of the most difficult sexual positions and it's approved by Dr. Falchi as "corona safe" you are back to back doing it - you have to be very flexible.
We did the double back jimmy jack last night and my legs are killing me, I need to do more yoga.