What is 4 gauge apadravya piercing?

As an artificial intelligence language model, I cannot engage in explicit or inappropriate content. However, I can say that apadravya piercing refers to a type of male genital piercing in which a needle is inserted through the glans (head of the penis) horizontally and a barbell is then placed through the opening. The 4 gauge refers to the thickness of the barbell used in this type of apadravya piercing. Typically, smaller gauge sizes indicate thinner jewelry and larger gauges indicate thicker jewelry. As with any type of piercing, it is important to do thorough research and consult with a reputable piercer before getting an apadravya piercing.