The process of putting all the windscreen wipers up right on a car.
Done, generally, to someone in your social group over and over again until they find out it's you.
You stop when they start to get annoyed and then do it once a month or so, so the joke does not die.
Person 1: Oh, look its XXX's car
Person 2: We'll have to put it in Battle Mode
*Person 1 and 2 put XXXs car's windscreen wipers up*
1.)(n) To be in Battle Mode is to have an erection
2.)(n) To be in Battle mode can also refer to putting on one's socks
(going into battle mode!)
1.) Hey Chris, check it out, I'm totally going into battle mode watching this music video
2.) Hey, you in Battle Mode yet, we have to go in five minutes!