It's not a real thing among normal people. It's actually a thing about jewish women though, because they abide by the talmud's teachings and everything is kikey nitpicking and loopholes. So there's a not-so-insignificant number of jewish women who will let you fuck them in the ass so as to retain their """virginity""". 

And then the kikes go and try to project their own fucked-up minds on to others, trying to pretend like it's catholic schoolgirls who pull this shit, when in reality its themselves.