To craft a Sword of the Zephyr, place a thaumium sword above a wand of lightning on an Infusion Altar. Then place 16 Aura, 8 Fractus, 8 Motus and 16 Telum in your crucible. This recipe will consume 100 vis from your wand.
If you right-click on a golem, and then exit out of the GUI, the sword will repel entities as if you were still blocking indefinitely, but you can still attack and move at normal speed. Note that this does not prevent fall damage. This effect stops if you block again or equip something else.