Getting more enthusiastic about BJs

So my boyfriend says he came to this scary realization that I'm not very enthused about giving him bjs. He's noticed that I treat it like a chore in the way that I move and offer no eye contact. That I do it more so to keep him from being unhappy while he goes down on me so that I can be happy. Given the freedom of choice I'd rather have sex than do that. He also says that enthusiasm is there or it isn't. I disagree on this. Can anybody help me out with advice or tips on how to be more into giving bjs? I'd greatly appreciate anything you guys can give.