First you need to take other songs and their beats . Then you try to get a picture of what kind of beat you want. After that try to ask a couple friends to help play it for you and say what they...
I think you are talking about the song "Cooler Than Me" by Mike Posner. It goes "If I could right you a song and make you fall in love, I would already have you right under my arm."
There was a Buck Owens song to which the complete lyrics were "This is the shortest song in the world." A bit longer, but still worth mentioning, is Shel Silverstein's "All the DJs keep complaining...