No no, I've never given birth!!

I'm just going off of what I've heard women say on here mostly. I do know that the pelvic bones in a woman do get wider when they've had children- you can tell on a skeleton usually if the women's given birth or not. Right? I'm not crazy, I don't think... I don't know if that's from the actual birthing process or just being pregnant though.
Hmm well regardless, the thing that will MOST effect your "tightness" is how lubricated you are and how turned on/relaxed you are. If you are very turned on and well lubricated, you might feel looser, likewise if you are really dry or nervous, you will feel tight (and it would probably hurt!)