Older brother says to younger brother as he wipes an astringent pad across his forehead: "Come look I've got puberty now."
Younger brother says: "Who cares. I don't. And no you don't."
Older brother argues as he pulls away waistband and points down to show more evidence: "Yes I do. You can see my puberty. Mom said."
Younger brother yells: "I DON'T WANT TO SEE YOUR PUBERTY!"
End of conversation.