mistermole7
Expert Member
It's not about "who", it's about "where". In a very patriarchal society, your dick is pretty much synonymous with privilege. Showing it off is seen as manly, because it's transgressive, strange. "My dick's bigger, here's the proof. Since this makes me manlier/better than you, I can choose which rules to follow".
Not really certain what this is supposed to mean, all I know is that mindfully comparing or showing off genitals to family members/relatives of either gender is odd and inappropriate.