From the time I was about 15 until I was 22, I could suck my own penis. I was in a motorcycle acident, and lost the ability after that. I could take the top two inches or so into my mouth, and would often suck myself to completion, swallowing my own semen. I guess that is where I grew to like the taste.
Now I can only hold my penis about 3-4 inches from my face, and shoot into my mouth. I do like giving and receiving facials, and really do enjoy the taste of semen.
I have been working on my flexibilty, but I don't think I will be able to self-suck again.