So your girlfriend thinks that tiny thing between your legs is useless, but I don't agree. Just because a woman wouldn't feel it if you tried to find a way to push it into her pussy, that doesn't mean it isn't good for *something*. Everything's good for *something*, right?
Let's go out to the pool while we try to think of some things it might be good for. You can help! If you come up with something, maybe you can tell her when she gets back. She'll be so proud of you!