Peeing in the shower

Do you pee in the shower? That is OK. I am not judging. But you should consider
that a shower drain is not the same as a toilet. The shower is missing the bowl full of water. If you pee in the toilet most of the pee is flushed down and you still have that bowl of water between you and the U shaped pipe down the way. In the shower, if you must pee,  you can plug up the drain and create the bowl. Then let it flush.                Peeing is the only option here. Anything else will probably involve a disgusted plumber. 

This also applies to sinks but not pools. With sinks, even if you are not peeing in them, you put stuff in the drain. If you are wondering why your drain stinks, think about what you put in there. If you just poured something in there, it is probably still sitting there rotting. Just as with a shower you need to flush it. Stop up the drain and let an inch or so of water fill up and then remove the stop and flush.