This thread brings to mind when I was a just lad reading the paperback book The Godfather. Sonny Corleone was described as very well-endowed. After he was killed, his mistress hooked up with another guy. Her time with Sonny stretched her vagina and she has surgery to tighten it. The operating surgeon looks up at her lover and uses his fingers to indicate what width he should use as a guide. The guy went with the lesser number.
Sorry I am not more specific, but I haven't thought about that in years; though it obviously made quite impression for me to still remember it.
Personally, I have not encountered such a vagina nor a butt-hole in my adventures.