There's a big long story about how I came up with the idea for this episode but it's very very boring and doesn't really matter so I'm not going to bother.
As far as Narc's shirt, it's meant to make fun of all the black t-shirts with white letters that have tough slogans like "I eat babies" or "Mentally Unstable" and so forth. I figured the world needs more that say fun things, hence "Puppy Dogs & Kitty Cats". It's available to buy in the store right now. http://www.zazzle.com/apt 404
Oh, and the song being referenced is "Car Wash" from the Car Wash Soundtrack. It's by Rose Royce.