I think both porn and the attitudes of other guys play into how men feel about their penises. Guys want to BE the biggest - and also often see giant cocks in the porn they watch - so, of course, they think or internalize that BIG is best. But, well, the law of averages suggests that most guys are average - and those average cocks are still having sex with vaginas - in fact, most of the sex being had involves an average cock. A healthy mind and confidence are super sexy - so learn to use and enjoy what you have!