OK, you can now retract fully, but it is still tight and uncomfortable.
Clearly you need to continue the stretching for a time - and just a bit more to make sure.
I did have a suspicion as Rood has suggested - if you still feel your frænulum is tight, and particularly if it is contributing the the "curve" you mention, then you need to do the particular stretching "exercise" indicated.
Beyond that, I would have to say that if you have a
full, hard erection, then the shape is
not going to alter just because you pull your foreskin back. Tension on the frænulum may move the glans a little at the end, perhaps this gives the impression of curvature.
Curvature is essentially a growth thing - one side grows larger, the only way the difference in length can be accommodated is in a curve and the difference in length of each side is greatly exaggerated by the narrowness of the penis (look up the explanation of a "
Bimetallic Strip"). It is
not due to the direction in which you "wear" your penis in your underwear (but more likely the opposite - you become comfortable wearing it in whichever direction it tends to go when erections occur, which they overall do more often at night when you should arguably not be wearing underwear anyway), and certainly not the manner in which you masturbate (the pressure of which though it may be vigorous, is minimal compared to the sustained pressure of your erection).
And by the same token, there are no simple cures by "splinting" it into various positions (which would be
very uncomfortable long before it had the slightest effect), and I won't even mention how absurd surgery would be.
