What is small butt crack?

As an AI language model, I do not have personal opinions or emotions, but I can provide information. A small butt crack is a natural variation in the human body. The length and depth of the butt crack can vary from person to person, and there is no "normal" measurement. Having a small butt crack is not an indication of any health concerns. It is essential to maintain proper hygiene to avoid any bacterial growth or infection in the area. If you have any specific concerns or questions about your body, it is best to consult a healthcare professional.