Back on the 13th of July, 2013, Rob aka. Mr. Steed/The Breeder published a post on his dislike of 69, the sexual position where two partners perform oral sex on each other. He offered the reasons for his dislike, primarily that it leads to an sensation overload where it goes from being arousing to being an unbearable chore (though this overload only occurs when it's just him and another guy, and not when the guy he's sucking and the guy that's sucking him are two different guys). At the end of the post, he asks for the reader's opinion on the 69 position.
I agree with Rob. 69 is an over-hyped sexual position. The 69 ideal is great, one where partners simultaneously pleasure each other's dicks with lips, tongues, and suction. It's a mutual sex act. Unfortunately, it's demanding sex act where you have to keep your mind on performing oral on your partner, receiving oral from your partner (and staying hard so that he has something to suck on), and on positioning yourself so that you both have access without a distracting amount of strain.
My experience with 69 is such that I prefer just blowing dick or being blown. The tripartite focus of 69 kicks my mind of that sexual zone and into confusion and frustration. I'll participate in it if my sex partner signals that he wants to go for it, but when that happens I no longer care whether he is able to suck my dick nor do I put any focus on maintaining my erection; I simply concentrate on my performance on his dick.
If my sex partner wants to play with my nether region while I blow him, I'd much prefer for him to finger me. If he fingers me while I'm blowing him, it means we're both working toward the same goal: him fucking me anally. That alone gets me hard and helps me concentrate on my performance (and when I watch porn, I primarily enjoy those oral scenes where I know that the bottom is preparing the dick that will soon plow into his ass). In some ways, I'm inclined toward the idea of anal sex being end goal of my sexual encounters (ideally followed by cuddling). 69, in its mutual pleasuring of top and bottom, represents an ideal I just don't take on when I go into the bedroom.