I rarely do it and if I do, do it, I am alone.
Once my partner didn't tell me and it smelt so trongly of piss i nthe shower...I was like "did you pee?" He was like "....yes" with a shy look on his face.
I'm not "its ok, whatever" I think if you have to pee in the shower do it alone. It can smell strongly, I personally do not enjoy this, but my partner doesn't seem to mind.