Its kinda simple, you need duel specc.
you can put earthshield on any1 in the raid / group but not on yourself because then it will go away.
you change specc and the shield will still be left on target.
this is a exploit because the buffs should dissapear, but it will remain on others when you change specc.
found some posts on it. but think it could need a refresh, because the last post was 2010/03/xx