MacLaren's. Ted tells Barney that he broke up with Stacy. He couldn't get Barney out of his head, like a Chumbawamba song. Marshall asks which Chumbawamba song. Ted and Barney just look at him. Barney says he's going to win. He explains his evil plan. We flash back. When he first went up to Stacy at the bar, he talked up Ted as a nice guy who was interested in her and asked her to slap him just to show Ted she's not into guys like him. "You are so sweet!" she says and slaps Barney. Barney explains that no matter what Ted does after that, he'll be even nicer in her eyes. "You never slept with her?" Ted asks. "Not even...at all," Barney says. Evil! Right after Ted's yoga phone conversation, Barney went and dressed up in yoga gear and carried a yoga mat, then pretended to run into her on the street. He referenced a reggae concert and said he was a huge fan; he even threw in a "See ya later, alligator." Slick! We see Barney throwing away the yoga mat he was carrying. Ted's a little upset because it belonged to him. Barney is about to go meet Stacy. He gives us the French for, "Cuz I got game, bitches!" Barney answers his phone. It's Stacy. She's telling him about the breakup. Ted says he should have just worn the eye patch.
Apartment. Robin's eating ice cream. She thinks the boy is a little stupidhead. She insists she's done with kids. SagetTed tells his own kids that they know the real story. She turned out to be a really good aunt appearing in very important art. We see children's drawings showing, "Us and Aunt Robin." No uncle anywhere.
Postscript. One month later. Barney is sitting in Stacy's apartment as she plays the bass guitar. He fake-claps. Stacy appreciates Barney being willing to take it slow. She doesn't want things to get too physical too fast after Ted. Barney is in Hell. Her concert the next day is sometime from 11 to 6 and she wants him to get there at 9 just to be safe. She also tells him it'll be muddy. Barney lies back, tortured. A reggae beat plays as a tiny Ted dances on Stacy's shoulder. Barney cries.