Every penis is built a little differently. Some curve down, and some curve to the left or right when erect. (Some point straight out when erect, others are hard against the stomach.) If it provides pleasure, it shouldn't matter what shape it is. Penis curvature normally develops simply from the organ's internal structures growing to unequal size, a condition that's quite common. In fact, it's rare for a man's penis to be perfectly straight.
I think that clears things up
. Oh and for the record, my penis curves very slightly upward