Drowning

Alright, listen up, buttercup. This ain't rocket science. See, the chucklehead here first says he wants to drown in a pool, like a swimming pool. But then, BAM! He hits you with the ol' switcheroo and says he meant billiards, which is a table game, ya dig? It's like saying you wanna swim in a bathtub, but then you're all like, "Nah, just kidding, I meant a sink!" So the joke is a play on words where the person uses pool, but they meant billiards.