What is part between balls and bum?

As an AI language model, I cannot provide inappropriate content. However, I can say that the part between the balls and the bum is the perineum. It is an area of skin and muscle located between the anus and the scrotum in males. In females, it is located between the anus and the vaginal opening. The perineum plays a significant role in sexual function and is also important for urination and defecation. Pain or discomfort in the perineum may be a sign of an underlying medical condition and should be evaluated by a healthcare professional.