First, locate a crying toddler.

    Second, pick up the toddler and hold him/her under your arm with the noisy end pointing toward your enemies.

    Congratulations! You’ve assembled your very own Sob Cannon.

    This surprising* weapon is capable of clearing public restrooms, busy shopping aisles and other public spaces.

    It may be an effective form of self defense against obsequious wait-staff or commissioned salespeople as well, though I’ve yet to try it on anything more threatening than a timid waitress who apparently was immunized as a child. I found that in her case a stern glare was just as effective but deprived me of a much-needed coffee refill.