As a dog owner and semi-retired dog trainer, I don't understand the humor you seem to see in your dog rolling onto her back and peeing when she "greets" certain people.
This peeing is a sure sign of distress/fear and your dog needs to be shown that there is nothing to fear. I hope you do some reading online and help your dog overcome her anxiety during such encounters.
Sorry. I don't like this one. Most bats don't bite and while I realize this is supposed to be humorous, I don't like the perpetration of the scary biting and getting in your hair bat myth. Plus, it's just not funny anyway.