How do I explain to him?

How do I explain to my boyfriend that I don't like my c section scar being touched? I had it almost 5 weeks ago and we were just in the shower together and he tried to touch it but then didn't understand why I flinched when he tries to put his hands near it. He's not the type to actually "talk" about things. And it's partly my fault too because when I try I studder and nothing comes out right, or I loose my train of thought, or cry. I'm pretty much worthless when it comes too that. But how can I put it in words to make him understand? I had a very tramatic birth experience. I went into early labor at 21 weeks and stayed in the hospital miserable until I was 25w3d and gave birth.