Like 4 and a half is average I'm pretty sure. Lemme Google. Okay Google says 5.1 but close enough I guess. It's WAY less than porn obviously and WAY less than women think. I have a strong hunch that this is because most men they've been with have lied about their size so to them a 4" is a 6" is an 8" etc. There was this green text I saw posted here today/yesterday about a dude with 5.5 saying "don't expect anything special" and his girl freaking out so this backs up said theory.
Bottom line it doesn't matter. The vaginal canal is like 4-5 inches and the g spot is just a couple inches in so you can do good no matter what you're packing. A lot of women don't like you poking their cervix. Also I have it on good authority some women prefer people without penises and they seem pretty satisfied too.
I once fell asleep with a laptop on my lap that had a horrible heat sink and would basically turn itself off every half hour. My legs were crossed when I fell asleep and my heel was right up against the vent.. Woke up with the laptop still on. Confused. And then PAIN. It has used my heel as a heat sink. MASSIVE burn, horrible pain, like four inch blister, still have the scar twenty years later. Had to wear flip flops for like a month shudder