Filling pneumatic skateboard wheels without losing air from air pumps

Here's a quick tip for anyone struggling to keep air in when disconnecting the pump from the valve. The tricks are simple:
1. Connect the pump as lightly as you can without leaking when you pump
2. Flick the trigger quickly to unlock without putting any sideways pressure on valve stem
3. Quickly and smoothly pull the pump of the vale as straight as possible.
With practice you should be able to pump tires without losing much air.