Bat out of Hell was a common rural expression in the southeast US a half century ago. Meatloaf originated the expression in 1976 or thereabouts with the mid-70s Zeitgeist eponymous album "Bat Out of Hell." The expression 'like a bat out of hell' has been in common UK-English usage for decades meaning to fly, usually figuratively. Bats have been associated with witches and the occult, and therefore thought to originate in the bowels of hell, as they fly quickly as if in panic, to make the comparison with a bat flying out of hell for anything going recklessly fast would seem quite natural and likely to be a country idiom prior to being recorded in print.
The act of fisting a girl while she is on her period. When you are finished fisting her, you pull out your hand spread wide open like a bat leaving the gates of hell.
I had my period last night and Gary decided to fist me. I thought it was weird, but then he pulled out his hand and screamed "Fly, Fly awaylike a bat out of hell!!!!!"