Sometimes, the person on the receiving end of oral sex is being pleasured, but also feels very vulnerable; meanwhile the giver, though performing an act that usually won't provide them with any direct physical pleasure, holds almost of the power in the situation.
For some people (even those who don’t particularly care for the act itself), it’s that power imbalance inherent in oral sex that gets them off ― further proof that sex is not just physical, but also about our emotional impressions and sensations.
I also think I like it because, honestly, I've been told by multiple partners that I'm good at it.
And it's a pretty big turn-on to be told that, and to go into it with the confidence that you're going to rock somebody's world, as it were.
Hence my general preference for partners who are either verbal or at least use their vocal chords during sex.
Like, even when he had just gotten out of the shower.
This is probably pure fantasy, but I feel like I would enjoy going down on a person with a vagina much more. Under the right circumstances I love it ― love the reaction it gets, love the power and gratification that comes from giving someone else pleasure.
I also actually like the experience of it, as long as I'm in the mood to be doing it.
However, when I was in college, I used to give blowjobs to pretty much every guy I had sex with, largely because I felt like it was expected of me and not a "big deal" compared to having sex.
And I am very, very, VERY wary of this kind of thinking now.