Well, that's easy, you create music first and then find lyrics that fit the music, but don't preoccupy with meaning. Just brainstorm words and focus on the rhyme and the sound of the words. For example "Do you want to be mine? Oh, baby, your so fine, I gotta cross that line and make you feel mine." LOL Although I don't know how meaningless that actually is?? It is shallow for sure. But, why do you want to make meaningless lyrics? I have a bunch of meaningless lyrics which fit good with the music, but I'm trying to make them meaningful now...
P.S. I think Anthony Kiedis is the master of meaningless lyrics!