I'm thinking monkeygirl is brilliant. This is the conversation that just took place within earshot of the ex
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MG: Mommy, Daddy is older than you
Yes he is
MG: Want to know how I know?
How?
MG: Because your boobs are just this big (makes a small gesture) and his boobs are THIS big (makes a big gesture)
Honey, Daddy doesn't have boobs.
MG: Yes he does! Have you seen him without a shirt?
Yes I have, and he doesn't have boobs. Men don't have boobs.
MG: Then why do they stick out like this? (makes a triangle gesture sticking out from her chest)
He has a regular man's chest
MG: No, he has BOOBS!