Today i was jumping my own rig for the first time. Exit height was 10 and deployment was 7, just to get a feel for the different canopy! On deployment of my pilot chute (From BOC) and starting my saftey count, i found after 3 secs i realised i had a pilot chute (hesitation) in tow, looking over my shoulder, "i am still to work out what happened next", in an instant ???? i found my self head down, on my back with the pilot chute in tow between my legs still in freefall! whilst reaching for my handles, the main deployed, but from where or how is still a blur .. Can anyone shed light on how i ended up head down and on my back, and where did the main deploy from there . Landing safley, i changed the closing loop and and borrowed a larger pilot chute .. opening was great and on heading.