Yes,started doing this as a teenager. Must have swallowed gallons of my own cum. Took me awhile to realize that I just liked to eat sperm. I love pussy but there's nothing like the feeling of a swollen cockhead jerking and spurting in your mouth!
I used to have a pretty teenage girlfriend who was fascinated by this after I showed her. She loved to stroke and aim it for me and she always got it right in my mouth. Yummmm
Your back must be really flexible. You should see if you can find a lady to wank it while you're in this position, and she could aim the ejaculation......it would be easier for you ?!