Slap Bet -

When Barney slapped Marshall prematurely, Lily granted Marshall "slap justice".

The Slap Bet was born in Season 2, Episode 9, titled "Slap Bet". The stakes were simple: Marshall bet that Robin was hiding a secret about being a porn star, while Barney bet she was hiding a secret marriage. The prize? One slap, as hard as possible, to the face of the loser. Slap Bet

When it was revealed that Robin’s secret was actually her past as Canadian teen pop sensation , both men were technically wrong. However, Barney prematurely slapped Marshall, leading to the appointment of the world’s first Slap Bet Commissioner : Lily Aldrin. The Role of the Slap Bet Commissioner When Barney slapped Marshall prematurely