Every healthy vagina can contract its walls! You can even train your vaginal muscles, vaginal weight lifting. We tend to clench our muscles if we get good amount of pleasure, if it's uncomfortable or if we have to pee but there is no bathroom anywhere :)
It's the muscles in the vagina that are contracting causing that tightness and yes we are quite aware we are doing it.
The lips are that baby soft skin which might resemble a hotdog bun one views before spreading them open
I can tell when it happens because I'm usually squeezing my muscles down there on the "out" stroke to make it happen.
Seriously, well done for doing that! It feels amazing when a woman really squeezes her muscles around the penis like that but in my experience not that many do it.
It's definitely more noticeable in the doggystyle position. Can't say that I fid it a huge turn on though.
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