The towel raise exercise helps increase the strength of penile muscles, which results in having more control over your penis. The first few times may seem a little awkward but stick with it. During this exercise, being fully erect is required. If your erection starts to subside, put a finger or two underneath the penis to assist with a few more reps.
Step 1: Place a hand towel on your erect penis.
Step 2: Lift the towel up and then down, try remaining in control throughout the motion.
When doing this exercise aim for 20 reps. Once you're able to do 20 reps consistently, intensify the exercise by using a wet towel to increase the weight.