I read the OP as he saw this chap emerging from the cublicle. So unless it's common practice for bikers to stick their heads down the bog after a ride it does seem strange. Although to be fair bikers do some very strange things.
Rather why than how but there's a guy I see in our office block that has a chat on his phone whilst peeing at the urinal, he then gives me a funny look when I use the hand drier meaning he can't talk as it's too loud
To be fair who cares so long as he isn't one of those wierd toss pots who fills the bog with an entire roll of bogroll in a big pile, then craps on top of it. WTF is that all about? Is it some kind of territorial marking thing?