There are specific exercises you need to perform for natural enlargement to occur. It's important to understand that it takes time and patience. I will give you 3 tips on how to enlarge your penis naturally.
First tip- The most important thing you can do to prevent injury is to do warm-ups firsts. These need to be done before every exercise session. Before you begin any exercising you should start off with a 2-5 minute warm up. One of the warm up techniques is to get a washcloth and soak it in warm/hot water (do not burn yourself). Then gently massage your flaccid penis with the washcloth (you can also massage with your hand). The idea is that the warmth and moisture will get it more elastic and loosen up the muscles and ligaments.
Second tip- Be patient. Don't spend two hours a day straining yourself thinking results will come quicker. The penis needs proper time to heal and regenerate more cells and blood chambers. If you put in a consistent effort it's definitely possible to gain at least an inch within the next month.
Third tip- Don't be too aggressive when doing the exercises. If any of them are causing pain then you're being too aggressive. Make sure you fully understand how to perform the exercises before attempting them.
For conclusion, I recommend you to measure your length and girth right now so you can notice your gains in the future and determine what exercises are the most effective for you. Tell yourself right now you will set up a routine and dedicate the time it takes to achieve real results. Inconsistency with the exercises will give you nothing.