My cock has a medium to large downward curve and my wife hates doggie because of it. She also said out of all the men she has been with I took the longest for her to have a orgasm with.
She has a very small pussy, so she blames most of it on it always being painful during sex, but after a few years she adjusted to the girth (still cant drive it deep without it hurting her) and she can now come like a animal. The only exception is doggie, which hurts her even when I only am going 1/2 to 3/4 into her. She used to love that position until she met me, so as you can guess I rarely get doggie now.
On the other hand, reverse doggie she loves and can have multiples while in that position.
She mentioned a few weeks ago that she wondered if there was any way to "straighten" my cock. I looked on the internet and found a few devices made by doctors that you wear continously for 6 months or so and they are supposed to take out any upward or downward curve. They want $500 for the things, so im hesitant to buy one until I can find out more about them.