1. A piece of pussy you keep on the shelf meaning you always know where to get it and you can get it when ever you want.
2. A homie who is boring and does nothing except "sit on the shelf," and collect dust. see couch potato
"so what are you gonna do today?"
"i think ill hang out with Christy"
"Who is Christy"
"Just a cute "shelf cat" I call whenever I need her"