Don’t ejaculate!!
That’s the key.
Your body naturally maintains your penis health through nocturnal erections while you sleep. Without it, you cock would shrivel and die. So, to get erections without ejaculation is helpful. And, the longer you don’t ejaculate the harder your erections will be which means more shear stress on your penile smooth muscle. I only ejaculate with my wife. By myself, I masturbate and edge without ejaculation as part of my routine. The longer you hold an intense erection, the more you’re stressing your smooth muscle.
Here’s something interesting, people with sickle cell anemia who experience prolonged erections called priapism may develop megalophallus. Priapism is an erection that lasts for up to 4 hours or more. Although priapism is extreme, gaining an erection for a good amount of time will increase the size of your cock. If you don’t ejaculate your erections will be better and last longer.