Quote from Barney in Of Course
Lily: It has been four months since you broke up with Barney. Maybe it's time to put yourself back out there.
Marshall: Yeah, exactly. Barney's dating again, and he couldn't be happier.
[cut to Barney talking to Ted, Marshall and Lily in the apartment:]
Barney: I couldn't be more unhappy. All night long, she's hot and heavy for me. I get her back to my place,
and she just bolts? I mean, at least, when I run out on a girl, I have the common courtesy to sleep with her first. It's called manners.