Having sexual urges is not bad; it's a sign that you're healthy. You should be worried the moment you don't feel any.

Controlling it depends on the individual. That's why it's important to find out your triggers. As much as feeling horny comes naturally, you can still be triggered to feel that way.

To control it, you have to study yourself and discover your triggers.
Triggers are those things that fuel your thoughts, especially when you're alone, leading you to either masturbate, watch pornography, or engage in premarital and extramarital sex with the opposite gender.

Your environment can be a trigger; your news feed on social media can be a trigger; your friends can be a trigger; your phone library and gallery can be a trigger. So take your time and study yourself if you struggle with controlling your sexual urges. Identify your triggers and cut off from them.