Ahahah!! I risk to pee in my pants now.
Anyway, yes of course, I pee in the shower everytime I feel the need... lol. It's just water with some salts inside, where is the problem? My kids do it all the time and I think my wife does it too (I will ask her later). You know, we're very sensitive to water saving... and the procedure is quite useful when we wake up with... uhm.. we call it flag-raising, only valid for men, of course... which causes the water-closet to be unusable untill the "flag" is down...