For one you should probably avoid the doggy position. I have a similar "gift" to yours. If you want to practice rear entry sex, whether vaginal or anal, you will need to find positions which do not over stress the angle of your erection. You on your back and your woman lying on her back on top of you is a possibility. Woman face down. This one might work or not-have her on a low bed or piece of furniture in doggy or with feet on floor, upper body pressed against mattress, you standing on floor but leaning way over, supporting your weight on your hands. You might be able to enter with your erect penis at a more straight angle rathewr than bending it down.

I also suggest you take a look at the illustrated sex positions on this site.

in doggy style, if man has long penis its more easy if not man should stick partner to avoid distance.

I would simply avoid the uncomfortable positions and change angles until the position is comfortable. Adjust the heights of your bodies relative to each other as well as the angle your torso makes with hers until you find something that works with you behind or avoid it altogether.