Many years ago I was "friends" with a 19yo virgin who refused to let me penetrate her (saving herself) but she loved for me to perform oral on her. She had very large labia that I loved to suck and stretch. She seemed to really get off on that so I wonder if larger labia might be more sensitive as well. By contrast, my wife has small labia and had sex with well-hung guys for many years and there was no change there but her tightness and "texture" definitely changed.