How To: Align yourself so you are near the object and can see the action icon.
Press R to shield and B to stab (some things you will need to move your shield to the right/left so you won't stab it and be moved backwards so that the action icon no longer shows). While in mid-stab (to be precise, while the sword is about to recede), press the A button to activate the action.
The blade will be glowing white while the interaction takes place if you've done it right. This will cause the sword to attack anything it touches, even while running. Notes: You won't be able to fall or jump off ledges.
