Small area to work wit... there's a uterus pressing up behind it, with a rectum psuhing pushing against the back of the uterus. Needless to say, when there is a baby in there it sucks. And this is all worsened by a short urethra and weakened pelvic floor muscles following child birth. There is very little wiggle room, unlike with dudes who don't have an extra structure in there and a much longer urethra.