I think I skipped this chapter of Uzumaki

Yeah, I stick things up my ass for fun, and am fine falling asleep with said toy in my ass and waking up an hour or 2 later and using it again. Your butt does not self lubricate and nothing you use as a lubricant will still be there later.

Point being, your body will make you painfully aware that you have a dry item with a flared bottom in Your rectal cavity.