What does this mean? (I'll shoot ya in your chest and I'll wet ya)?

I was watching the movie the original Kings of Comedy and Steve Harvey was talking about how rap music doesnt sing about love no more and gave an example saying "I'll shoot ya in your chest and I'll wet ya". What does this mean? Did he really get that from a rap song? Did he make that up? A week ago I heard kids saying that to insult some other kids. Where did this come from?