If you aren't familiar with how a "slap bet" works, please allow How I Met Your Mother's Marshall Eriksen to explain: "Whoever's right gets to slap the other person in the face as hard as they possibly can. But no rings."
The best thing about the slap bet is the fear it instills in the loser as they tentatively shuffle through life waiting for the other hand to drop.
On their face.
Such was Steven Dalton's fate, until his friend Zane finally decided to collect — right in the middle of his own wedding.
As Marshall says to Barney: "That's one."