Yeah, surprisingly you can do about anything. Lasts maybe 15-20 seconds? I initially thought it would be 'just guard for that turn' making it useless in all but specific scenarios, but no. It just means 'put your shield up for awhile and do other things in the meantime too'. Very useful, actually, especially teamed with Phalanx, which seems to hit harder than normal strikes (now, anyway) while costing half the stamina.
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