How do you you use frenemy in a sentence?

Frenemy is slang, and not an actual Word so it isn't used by most people in formal conversation. But in slang, it was created (and new Words are often created; they sometimes begin as slang and then work their way into the dictionary) to refer to a person who is both a friend and an enemy-- perhaps someone about whom your opinion frequently changes, or someone who is only a friend sometimes but feels like an enemy at other times.