Mmh, science says otherwise. The vagina expands when we are excited, typically! Sure it contracts during pleasure/orgasm but muscle contraction =/= being tighter.
I agree with science, but I can't help thinking sometimes situations can feel backwards. Everyone's body reacts differently, under different situations. I think my comparison comes in between an at rest and at use situation. Flexed mucils vs relaxed ones arousal aside as that seems to affect the flexibility inside once aroused. And I guess position plays a role too.
Text books aside, as sometimes we can be told something about ourselves, and find the general rules don't seem to always apply, curiously enough. For all I know, it is just self evaluation comparing being aroused or not, and with what it feels like with thinner rather than girthier members.
Or like a guy, it makes a difference with arousal as blood flow is redirected to genitals male or female parts once aroused. With the added blood flow, some plumping up happens with added blood flow, likely what I am noticing.