I find peeing standing does take different muscles and the way you relax. This is the case for whether I am in the shower with no stp or when using a stp. it is best to have lots of time and no one around when you try using an stp so you can feel relaxed. My problem is using my stp through the fly in my jeans, the zipper doesn't seem to go down far enough to get it the end low enough to have good flow out. It goes better if I loosen my belt enough so I can pull my jeans down about 2 in, then I get good flow out and keep it up tight against me so not to leak or back flow.