First Grade Insult

Alright, listen up, buttercup. The joke is that the dude's girlfriend is super young, like first-grade young. So when she calls him a "pedophile," it's funny 'cause she's just using a big word she doesn't understand. You know, like when you try to use words like "quantum entanglement" but you really just end up sounding like a potato trying to do astrophysics. No offense, but you probably still use training wheels.