You can feel it. It's being gripped firmly and stimulated hard when you're inside, rather than being caressed as with most women. If you've had sex with more than five or six women, you will feel the tight ones.
An example, possibly the most beautiful woman I've ever met, part-Thai and part-Australian. Very tight, I eased myself in and within a couple of thrusts I felt stimulated enough to get close to comming. The only way I could have sex with her was to change missionary position to kneeling between her legs, and then thrust very, very slowly and deliberately. She was too tight to do it any other way and have it last more than a minute. Doing it this way she got off (in this position, her tightness guaranteed that my thick cock was rubbing her g-spot with every stroke), and because it was doing it slow and deliberatly, I could last a fair while.
For a guy who's had sex thousands of times, and regularly so many times each week, to get this stimulated is really what tight is all about.