I remember some medical story where a middle-aged woman came in complaining of not being able to have children, with a history of A LOT of urinary tract infections and incontinence problems. So the doc takes a look but can't find anything. As in can't find her uterus at all. Thinking he must be crazy he brings another doctor in, who can't find anything either. So then they checked more carefully and found out that there was actually a "flap" covering the important business. Somehow her urinary tract had become stretched out enough to cover everything else, and her husband had been shoving his cock up it for years, hence the frequent infections and no babies. She never thought anything was really amiss because she figured it was natural for sex to hurt a bit for the woman.