Self-Baptism

Alright, listen up, buttercup. So, the joke here is that someone tried to off themselves by drowning—get it, like baptism but for kicking the bucket? But they messed it up and didn't die. Since they didn't die, it wasn't suicide, just a really sad attempt at a bath. People call baptism a cleansing, like washing away your sins, but this dude just washed away his chance at being alive. Which, considering you're asking me to explain a joke, might've been a better choice for you.