This glitch is actually very easy to do. Firstly, webswing or wallcrawl or whatever it is that you do, just get to the top of a really tall building. Next, wait for one of the petty crimes where someone is going to fast and says stuff like "OUT OF MY WAY YA' MORON". Jump from the top of the building and onto the car with the crazy driver inside. Beat up that car you usually do, but instead of flying up and getting your health. He jumps up, does a backflip, and lands on the car again, bouncing like a ball. It'll be like you still hit the ground, even though you didn't.