Much like in sword swallowing, this can take a lot of practice. The sneeze reflex is one of your body's defense mechanisms against bacteria and viruses-- when you sneeze, you forcibly expel particles that could make you sick.In other words, a human blockhead ignores one of the tools the body uses to prevent illness.neezing is a largely reflexive act that usually occurs when something irritates your nasal passageways. As with all reflexes, sneezing involves a reflex arc consisting of a receptor, a sensory nerve, an integration center, a motor nerve and an effector. Here's what happens: