Like Scissors and Paper

I have the shoes, you have the socks. We can be snug together but you like things hard as rocks. I'm an eraser, just tell me when and I'll be there, only if you don't freaking use a pen. You have a key, and I have a lock it fits perfectly, but to open the door you'd rather knock. So puh-lease boy, gimme a go I'm sure we'll make a great cameo!