Not really sure... But, it reminds me of this... What did the nail say to the screw when it saw a hammer coming down upon them?
I'm not a pool, a tree, a slave, a website, or a shirt. What am I? Just use left click on your mouse and highlight the answer below this. A book. Not a pool but it has a cover, not a tree but has leaves, not a slave but is bound, not a website but has pages, and not a shirt but has sleeves.