Take a look at this video by Sports Media Group. It shows the 2014 World Champions, the Australian mens hockey team, training the short corner.
The drills uses a full attack battery and a full defence and, in order to maximise the drill, a second bad is introduced by the trapper, in this case, Eddie Ockenden.
He places the ball on the top so does not have to worry about an exact trap. Aran Zalewski then executes the drag.
This exercise maximises the training time available for the drill. Obviously, the individuals still practice their short corner injection and trapping as well.