How can I straight my curve penis

You can't. You get what genetics gave you.

There are a lot of medical conditions which are either inherited or acquired can cause curved penis.there are now lot of corrective surgeries available now.you can consult your doc for the options.

Majority of men have a curved penis. Genetics could be a reason but mostly it happens because one wears a tight fit underwear while growing up that does not leave room for penis to become erect when it tries to. In our teenage we get erections several times a day and sometimes by simply looking at a picture. There is not much one can do now because the tissue has developed in that shape over several years. It can't be fixed without surgery and even with surgery there is going to be scars and damage to penis that you may not like. Internet and marketing from companies show large, straight and huge penis but that is generally a glorified form.