How I Met Your Mother S09E14:

Slapsgiving 3: Slappointment in Slapmarra

IMDb 8.4 22 min/episodeRelease:2005
In an attempt to deliver a devastating final slap to Barney, Marshall explains how he mastered the Slap of A Million Exploding Suns.
Genre: Comedy - Romance
Director: Pamela Fryman