We just used this potty seat on a 3 week trip across the country. It worked great for my daughter, on all different kinds of toilets in the US,and Mexico,even on the plane toilet. She is confident on this seat as it is very secure on a toilet, unlike the other brands available, and I tried them all before this. The first time I used it I couldn't get it to fit either, until I got out the directions and realized it has to go over the toilet seat with the rim in the front hanging OVER the toilet, and pulled up snug right againnst the toilet. It covers everything your child would touch on a public toilet, and my daughter had plenty of room between the sides of her legs and where the handles are.I use paper potty seat covers that I carry with me in a plastic ziplock bag with the potty seat and put one of those down before the potty seat, so I don't have to clean the potty seat every time it's used, which makes it practical for traveling.I have NOT had any problems with pinching or injuries,because the hinges are covered on this model, unlike the other brands I tried, which fell in or sagged or had moving uncovered hinges which would pinch. This is the best on the market and I've tried them all and this works. I won't give it a 5 star rating, though, because the covered seam hinges, which are necessary to prevent pinching and injury, stand up a bit. This means that if you want your child to slide forward or backward on the potty seat for a better position, you have to pick them up and move them instead of having them slide, or the seams where the covered hinges are could possibly irritate or scrape your child because they stand up. I suspect the woman whose son's bottom bled may have scooted him along the seat against these seams. Is it a perfect seat? No. But if you are aware of the flaws and never slide your child while they are seated on the seat, it really does work on every toilet in several states and Mexico if you read the directions first and be sure you know how to use it before you put your child on it.I do wish Primo would find a way to flatten those seams a bit, but as I said, I tried every other brand out there first and this is the best. Many other brands have uncovered hinge seams, and that is far worse, because then the seat can collapse or unfold at the unlocked, uncovered hinges, and if your child moves at all on that type of seat, they will end up with their bottom caught in the hinges for sure, causing a far more serious injury than an avoidable surface scrape.