During a colonoscopy, you will lie on your side with your knees drawn up towards your chest. A small amount of air is used to expand the colon, so the doctor can see the colon walls. You may feel mild cramping during the procedure. This can be reduced with deep breathing. The colonoscope is slowly withdrawn while the lining of your bowel is examined. A colonoscopy can be done under MAC, which stands for Monitored Anesthesia Care. This sedation method is performed by anesthesia professional who is in the room with the gastroenterologist and a nurse or technician.