Details
Open with /juggler or /juggle.
Shows how many torches you have left in your bags.
Shows your progress towards 40 torch tosses in Dalaran.
Keeps a timer once the achievement's 15 second counter starts.
Once you've opened the Juggler window, your mousewheel will automatically use and target torches as you spin it. Close the window and your key bindings will be restored.
Notes
Doesn't work in combat!
Don't forget to aim!
Is Juggler getting stuck? Mods like SnowfallKeyPress (http://www.wowinterface.com/downloads/info15078-SnowfallKeyPress.html) that adjust key bindings might break Juggler with certain setups. If Juggler shows a targeting circle on the ground but doesn't throw a torch, try disabling SnowfallKeyPress while you juggle.