I'm pretty sure one of you wrote something for it for Yuletide or something and that's where I first heard it.

That was me! See, I can prove it. My diabolical plan to get you into all of my fandoms is going so well. As for the beer commerical at the end, I think it was just a moment of Perry thinking of the dad seeing Harmony's commericals, even though some other girl has the job now. Like, she was too good for the dad, too good for her small town, and too good for the stupid commercial all at the same time, you know?