solosuck forums!

hey al! I was wondering if i practice long enough, will my back get used to the c-position and if i wont even realize the uncomfortable-ness

There's no way to say for sure what any man's body will or won't do, but if you're careful and do non-self-suck things to develop and maintain your flexibility (like yoga) then you'll have a much better chance of comfortably sucking your cock for years to come. Do some backwards bending! If you just do forward bends you'll end up with unbalanced muscular and connective tissue development.
I have always been most comfortable with the C and the plow - as I've said before, I never enjoyed the X because I felt that it was too restricting, but there are plenty of guys who thrive in the X - listen to your body and do the positions that make the most sense for you.
There will probably always be some discomfort, if only because it's natural to keep on pushing for more depth - even if you're swallowing your cock down to the balls you'll probably keep on pushing for more - but the more depth you have the more comfortable you are in the less deep bends.
Be careful. Enjoy your body, wherever you are in your self-suck practice. It's all about pleasure!
Al

ive been home sick sll day and ive been doin a lil yoga and a little selfing practice

Great advice Al! I always do a light stretch in the mornings and deep, intense stretching and self-sucking at night. Never try to SS in the mornings, you could hurt yourself.