Inspired by the Nerds candy. As with many things, the Gnomes added a G to the beginning of the word!
The G.N.E.R.D. Rage achievement requires a character to "Earn 50 honorable kills while under the influence of the G.N.E.R.D. buff. It's a slap in the face!". These are cumulative, they do not have to be from the same PvP event nor from a single instance of the buff.
However, prior to the hotfix, the duration of multiples of this item was determined by the first one obtained (the shortest remaining duration) after which they would disappear and the duration would reset for additional ones obtained. The system did not track individual candies from the stack, so had no way of knowing that you ate the oldest one and did not extend the timer when one was consumed. Basically, the clock started when you received your first one, and did not reset until they disappeared or you had consumed them all.
This aspect of how the item works has not changed. Your stack of these will still be treated as a lump that all expire at the same time. In fact, by trading all of your candies to another player and getting new ones from a Handful of Candy, your old candies' expiration timers will be set to equal the timers on your new candy when they are traded back to you.
This item does not bind and can be transferred. However, due to the timer issues already noted, this means that when you obtain one from another source, your whole combined stack will likely obtain the shortest remaining lifetime.
The effect of this item stacks 4 times and has a duration of 30 minutes.