Exercises that target the corpus spongiosum

I’m not sure if there’s a specific method that will target this area or if it’s just something that grows with PE. I’d like to get that ‘ridge’ along the bottom of my penis, and from looking at a few diagrams it seems like this is defined by the size of the corpus spongiosum? Is this something that’s just genetic or is there a way to bring out more definition in that part of the penis?

Look at drilla’s clamp-o-rama thread. He definitely enlarged it.