Russian contortionist/juggler Vladimir Tsarkov, performing as "The Red Harlequin".
This unique act earned him a gold medal at Cirque de Demain in 1986.
This is the full act, from Circus Benneweis 100th in 1987.
3-7 rings
Behind back, neck and machine variations of 3 ball tricks, also reverse contortionist, video quality isn't perfect but tricks can be easily defined, criticisms welcome.