This trick is a bit rough in the edges. To try to use it when you are dressed in a three piece suit is therefor not a good idea. In the right setting (barbecues etc.) never the less, it will do the trick just fine.
Place the lighter firmly between the thumb-, index- and middle finger. Make sure that non of the fingers are blocking the cap.
With a quick wrist twist upwards, the cap will bounce up.
With the striking wheel facing down, roll the lighter over a suitable surface to ignite the lighter.