I used to be able to do this, when I was a teen. Sitting on my bed, with my knees bent and legs spread in a flattened diamond shape, hands at my feet, I could bend forward and take the upper third or so of my erect cock into my mouth.
The first time I did this, I was surprised at how hot my glans felt. I would suck lightly, and it felt good, but I could never hold that position long enough to come.
I've never had another man's cock in my mouth, but I didn't feel any different about this than about having my own cock in my hand.
Years later, in an outdoor yoga class, our female instructor had us trying to put our right feet behind our heads. Most couldn't, but from a similar position as described above, I could do it pretty easily. Seeing this, she asked me to try putting my left foot behind my head simultaneously, as long as I could do it without pain. It took some doing, but a few moments later, I had both feet behind my head.
It was a little (deliciously) embarrassing, because in that position, my genitals were bulging under my shorts and were only a small distance from my lips. A few of the watching women giggled, and one of them, "Sheila," said to never mind what she was thinking.
I'm pretty sure that in that position, I could have taken my own cock in my mouth again, if my pants had been off. I had a nice little fantasy then and there, about a couple of the yoginis stripping them up off my hips and pulling them to my knees, then helping me do just that.
It didn't happen, but I like to think that Sheila was thinking the same thing.