Girls: How do you feel about going down on a guy?

This guy keeps asking me to go down on him and I refuse each time. I don't feel comfortable doing that with him especially since I'm not in a committed relationship. He was pretty sweet about it but I couldn't help but I feel like I was disappointing him. There's just something about it that I find degrading in a way (I'm not saying I would never do it) I can't fully explain it but does anybody else feel the same way? I think it's because of the way some guys talk about it.