This Sigil can hold up to 5 other Sigils at a time, providing you with their passive effects and allowing you to activate them on a whim.
Press [bloodmagic.keybind.open_holding] while holding the Sigil to open its inventory.
Press [bloodmagic.keybind.cycle_holding_pos] to cycle forward, or [bloodmagic.keybind.cycle_holding_neg] to cycle backwards. holding [Shift] and using your mousewheel also works.
As you have the Curios API installed, you can equip this Sigil as a charm. If you want to wear more curios at once, consider using the Socketed Upgrade for your Living Armour.