The fister can elbow deep into the rectum before reaching into the door of the sigmoid. The sigmoid Colon is also called in Depth fisting The S-curve. The Sigmoid Colon is approximately 40 cm long. and it's coming after the rectum. Here is the information you need to began Anal Depth Fisting, We step-by-step guid you with instructions on how to safely and easily gain access to the Sigmoid Colon.