"Bless Me" is used jokingly, or not, when asking for sexual favors from a young woman who attends a catholic or parochial school. This is referring to the hookup as a blessing to the guy.
John: Hey katie, want to come over and watch a movie?
Katie: A movie sounds good, but, seriously, you need to stop trying to get into my pants.
John: Oh, it's not your pants, but that cute little uniform I'm interested in. Bless me baby!
Katie: John, you're a pig.