In puppetry, the work of a second puppeteer assisting another by manipulating a hand-and-glove puppet's second hand.
A hand-and-glove puppet will require the lead puppeteer to place one hand in the puppet's head to manipulate the mouth, and his or her other hand will work one of the puppet's hands/gloves. This leaves one of the puppet's hands lifeless. There are two workarounds: the first is to allow the hand to swing freely, often with a thin string to hold the arm at a level equivalent to the working arm (Occasionally, as with Big Bird, the string is attached to the working arm and strung through the body-- when Big Bird raises his working arm, you'll notice the other arm retracts into the body). The second workaround is to have a second puppeteer work the hand.
The job for the second puppeteer is known in the business as "right handing" (The first puppeteer, if right handed, is likely operating the puppet's head with their primary hand, leaving their own left hand to operate the puppet's left hand, and so needs a second person to operate the puppet's right hand). The job is called "right handing" no matter which hand the puppeteer is working (there's not a separate "left handing" job).
Frank Oz started with the Muppets right handing for Jim Henson (for Rowlf the Dog) on The Jimmy Dean Show. With television puppets, such as the Muppets, both puppeteers are hidden, so audience members may not even be aware of a second puppeteer. "Right handers" are obvious in shows where the puppeteers are visible, such as Avenue Q.
Stephanie D'Abruzzo. Jim Caruso's Cast Party. July 2, 2004.
<http://multimedia.wisdomdigital.com/bww/castparty11.m3u> (29 May 2005)
David Regan. "Puppetry Construction Methods: Hand Puppet Construction." The Ballard Institute and Museum of Puppetry. 2003. <http://www.sp.uconn.edu/~wwwsfa/library_howto_handpuppets.htm> (29 May 2005).