Poopjuice is the lubrication remaining inside your anus until a turd has exited. Poopjuice is then expelled in a small drop or drip, possibly unoticed.
You know, when you have the perfect solid turd, with a clean getaway, theres always thatlittle bit of slime thats leftover, thats Poopjuice.
Also, can be seen in dogs after they crap and pinch the last bit off, out comes Poopjuice.