As the previous answerer said, we get more pleasure from something that is tight. For example, if you are using your hand on a penis it feels much better if you tightly grip it then loosely. Same concept applies to the vagina.
Loose vagina = less friction = less stimulation for the guy. Dated a girl once who had a child and she was really loose, had natural childbirth (why lots of women want C-sections). Unless I was really horny she had to give me a BJ first to satisfy me, then she would ride me like a cowgirl until she was satisfied. She was really good at BJ's so I didn't complain!