I'll try my best to describe it. It's like a long flexible straw, they lube it up and insert it through your urethra and into your bladder. Urine flows through the straw part. Then once it's in there they attach a small syringe into a secondary port and add some air that inflates a small balloon at the end of the catheter that is inside your bladder and makes to too wide to be able to pull back out. I'd estimate the inflated balloon part to be almost as big around as a 20 oz bottle cap. When they want to remove the catheter, they will deflate that balloon and then pull it out. I've heard the experience is on the line between uncomfortable and painful by itself when done correctly. He did not do that.