It's called a midline groove and is formed from the compression of the right and left pectoral muscles. :3
You're on quite a roll today. This is great, anyhow.
Awww, I look great. Thanks DILeak you are awesome, will commission again.
I like his expression.
*scrolls-* whoa, wait a sec *scrolls back up*
This here, this is fricken cool looking!
. . . do want