Letting the Suicide Pun Hang

Explain Bear here, listen up, buttercup! This joke is super dark, just like your future. The speaker says they have a suicide joke, but then use the phrase "let it hang." This is a pun! "Let it hang" means they won't tell the joke, but it also darkly references the act of hanging oneself, which is a method of suicide. You're welcome, you dullard.