I do.
I aim for the drain - to be honest, piss is 98% water and 100% sterile anyways, so it's really not a huge deal to me. I clean my bathroom regularly if that makes a difference.
If I've gotta piss (generally a side effect of the hot water of the shower), I'd much rather just go in the shower rather than jump out, dry off, and go to the bathroom or jump out, drip water on the floor, and risk slipping on wet tile and knocking myself silly.