It reduces the cooldown on OFF Global Cooldown abilities (ex. Blood for Blood). However it only works if the Spear is given to the person BEFORE they hit the buff. So if they use Blood for Blood and then you give them a spear it will NOT reduced the cooldown. It's is pretty useless without coordination and no DPS is gonna wait for a Spear in order to use their CDs. So it pretty useless and only used for Royal Road.