Suicidal Jokes

Alright, listen up, smarty pants. The joke is dark, like your future if you keep asking dumb questions. The person is saying they don't make suicidal jokes because they're living one, meaning they're suicidal themselves. It's funny because it's unexpected and, let's be honest, a little messed up. You probably didn't get it because you spend too much time thinking about what flavor of crayons to eat next.