This is a brilliant electrical engineering dad joke that works on multiple levels! The concerned parent posts about their son eating electrical cords, and Geoff responds with "Ground him until he conducts himself properly." It's a perfect triple pun playing on:
1. "Grounding" as punishment for kids
2. "Grounding" in electrical systems (connecting to earth to prevent shock)
3. "Conducting" as behavior vs. electrical conductivity
The shocking truth is that proper electrical safety is no laughing matter, but this response has 100% resistance to being unfunny!