I think my boyfriend is afraid to go down on me.

I always give boyfriend head and every time he's like "I owe you one" and so last time I was trying to be nice and I told him that he doesn't owe me anything and I like doing it, which I do because I like making him happy. But tonight we were messing around and he like went down like he was going to but would only finger me. He was like kissing my thighs and everything but just wouldn't do it. He's done it before, and He claims he likes doing it, but I think he's lying. 😣 Is there a way I can get him to without coming right out and asking? I can't remember the last time he's actually returned the favor 😩