Much clearer explanation, from the video’s page:
This is a fast and simple vehicle swingset tutorial.
Follow my steps in the video, so you know how to do the swingset glitch.
The steps are also in the video description on Youtube.
This works on both the PS3 and Xbox 360 as of now.
This is the location of where the swingset glitch is.
This can be done by any vehicle, but it is hard to do this glitch with a motorcycle because there are high chances of you falling off.
You have to go slow onto the swingset with your car.
Once you reach the middle bar, hold X (PS3) or the brake button.
While holding the brake button, hold R2 (PS3) or the accelerate button.
It sometimes works without holding R2.
After a few seconds you will be catapulted across the map.