believer hit
The believer hit is the last hit in a pipe. It's mostly ash, so there's a chance that you'll get a mouthful of ash if you don't believe in yourself.
Tom: There's a believer hit left if you want it.
Steve: Fuck! I just inhaled a ton of ash.
Tom: Dude, you didn't believe hard enough.
Steve: Fuck! I just inhaled a ton of ash.
Tom: Dude, you didn't believe hard enough.