The male organ i.e. penile structure is not made up of bones but contain strong muscles that eat up more blood and retain to stand up and remain erect while the man is aroused s*x.ually. Said this,when the man is s*.xually excited seeing n*.ked woman or during the for.eplay, the muscles of the penile structure retains the blood and make the organ erected. The best hand exercise to make p.enis bigger based on this is stretching it naturally. During the day, stretch the organ downward (when it is not erected of course) a few times. This naturally lengthens the structure and you get bigger organ.
The second answer for how to make your p.3nis bigger naturally by using your hands is massage it upward when it is
er3cted. For this, you can manually erect the p.enis using handsand once it is stood, you can put it upward.
Do this gently and a couple of dozen times. You can practice this 3-4 times a day for 3-4 months to see visible results. The muscles in pe.nis are similar to that of what you have in restof the body (say biceps). But then, these muscles grow bigger when they retain the blood. Building these muscles is quite similar to that of biceps and triceps. You can use traction and lift it with er,ected penis. A very little weight can be tied with glans pe,nis and as you do a weight lifting using arms, can do with p.enis. However, you must take care that you should not use too much weight there and lift the traction gently.