Ok so im pretty new to swimming with jammers. I picked up a pair today, Nike size 32. My waist size is a 34 but most of my jeans are 32's. I haven't swam in them yet but i but them on for a min and walked a little bit. They are pretty tight in the crotch area and around the legs. After taking a few steps in them they keeping coming loose around the ass crack(for the lack of a better word). They are sliding down a bit. I have decent size quads and glutes. So should i go a size up or what? Btw, im 177lbs if that matters.