Freezing a piece of feces, so it will be hard, like a dildo. The frozen piece of feces is inserted into the sexual partner's anus, like a dildo. This is known as space docking. Once the piece of frozen feces is completely inserted into the anus, it is pooped out onto the other sexual partner. It is a piece of feces that is being pooped twice. Hence the name Twice Baked Potato
Bob took the frozen piece of crap out of the freezer, and put it in Jerry's booty hole. Jerry responded by crapping the crap onto Bob's tits. Jerry turned that space docking into a twice baked potato.