Let's not jump the gun here and assume this is just some nasty homeless fucker washing up in a public bathroom. Maybe it's a business man who took off his suit so it didn't get all wrinkled while he shat. And when he dropped a big deuce, it splashed and get his asshole all wet, so he had to dry it off. That's possible. But more than likely he's just trying to dry up all the semen dripping down his anus.