The Kama Sutra, refering to genital sizes only, uses three names to describe men and women. Mice, Deer, Elephant. The Kama Sutra recommends everyone stick to their own size, and the one next to you. That means Deer can be with anyone, But Mice and Elephants have to be a little bit careful. As far as I know, the Kama Sutra gives no instruction as to how to pick appropriate genitals without visual inspection.
I'm naturally virgin-tight too. I've had sex with my man almost every day (sometimes more) for over 2 years and he still has to work to get it in. It doesn't really hurt though. I get wet pretty quickly if I'm in the mood and if I'm not we just don't have sex. Anyway, so that's a good thing? I know he enjoys it but I always thought it was a little weird.