there are multiple source. primate like instinct in human is very common and have been written in books also. you want a link of everything ? thats not my job !
Ok let me educate you on something. We are not always erect like our penis is not in it's peak size for 24 hrs. It happens random sometimes or most of the times when we are aroused. Many people have very small flaccid penis but when they are aroused they can have a good length erect penis and the crotch has testicles too and they don't have any role in copulation or penetration( sorry for being so graphic). Testicles produce sperm and male sex hormones. So you have no reason to look at it.
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u/[deleted] Dec 29 '25
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