Start doing this for a stronger penis. squeeze your pc muscle (fells like stopping urination) release and repeat.

Before starting your exercise, rinse warm water on your semi erect dick for a few minutes and give it a gentle stretch to get the blood flowing

Forming an ok with your fingers, move slowly up the shaft squeezing it outwards, stop before you reach the glans. You can alternate hands.

While holding the ends of your shaft, bring your hands closer, focus on compressing the sides of your dick where the meat is. Don't swell your veins or stretch your skin.