Swing out and rise into an Uprise position at the backend. At the peak at the frontend, throw the bar forwards and upwards over your head and drop underneath to catch.
You can find out more about this trick in my books:
Thanks to Fred and Pedro for providing videos for this page.
IMAGE CREDIT: Thanks to Emerald City Trapeze Arts. Flyer is Laura Scoop. Thanks to David Treadwell for the photo.