I masturbate daily in the shower. I don't stand up though, I sit down in the corner with the water on me, think of naked girls, and it feels good. Just lay back and rub, and when you're about to ejaculate, lean forward and aim for the drain. There is almost no clean-up. Sometimes I do it out of the shower. (OK daily) and I like it better out of the shower, but it feels just fine in the shower too. I can usually cum in about 3 min.