I know of nothing specific for the toilet to prevent what you are talking about, and had the same issue with my know 6 year old, but having him stand won't confuse your daughter, my daughter wanted to stand to pee also and I would just explain how boys and girls are different and we girls aren't lucky enough to get to stand and pee that we have to sit, of course she didn't like that idea and even once tried to stand and pee :) but once she discovered it didn't work for girls like it does for boys she never tried it again, it was pretty funny, she was a little grossed out by the fact it went down her leg instead of into the toilet LOL. I would say search the internet, good luck.