Possible alternative conclusion that would require more research: Penile size increases when threatened.
when threatened. because diverting useful oxygen away from your brain/skeletal musculature is really the last thing you need when youre threatened. is this super straight alpha male logic where an oh my god 9inch wiener scares a raging grizzly away? "nope, i could utterly destroy this guy but his genes are to be protected because he has a nice dick".
by what logic is a straight person threatened by a homosexual one? by their very definition, they wont even steal your mates.
oh wait, by consensus im stupid so you must be right.
edit: ill explain this for you because you seem to not get the part of anatomy that seems to be the most important to you.
you have a standard dick size. when it gets smaller, its because its exposed to cold, to which your capillaries (small arteries, the things blod flows through) shrink.
when it gets larger, like boner large, its because a ring muscle relaxes, letting blood flow in.
if you want to understand this a bit better on grade school level, next time you have a boner, quit breathing. after 10 seconds your erection goes away because your body needs the blood elsewhere.