It might just be like other skills where you need to shift or click on a target to cast it.

Items for trade:
Windhorn, Eagleforce, Doomfather, Grandbringer, Harlequin Gaze, Vampirecrest, Gladiator's Valor, Arkaine's Bane, and Shaftstart

Looking for Stone of Manald rings. Also, I want Hearld of Arreat and Zakarum's Face.