A slight sideways curve in the penis when it is erect is not unusual, and should not in any way interfere with normal sexual activity. A slight upward curve in the erect penis is totally normal. An injury to the penis may cause scarring on one side and a significant curve (Peyronie disease). This can be corrected by plastic surgery. Unless the curve is quite severe all that is required is a large dose of reassurance.
Even with a significant degree of curvature it is still possible to have sex successfully, and it is unlikely that any woman would be particularly concerned about the degree of curvature of the penis at that time – presumably she would be rather preoccupied.
If a man is concerned, and after some sexual experimentation finds that it causes some discomfort, and wishes to take things further, he should trace the outline of the erect penis on a piece of paper. This can then be shown to a doctor to demonstrate the extent of the problem and further surgical treatment options can be discussed.