Start potty training. Read "Diaper Free: The gentle wisdom of natural infant hygiene" Yes, it's a completely dorky title. But it's a useful book.
You can also research Elimination Communication on the web.
My firstborn started pooping in the potty when he was four months old. My secondborn pooped in the potty for the first time when she was three days old. It is a complete myth that children aren't physiologically ready to use a toilet until they are three years old.
Please do remember that toilet training very young children is a completely different process from training older kids. Do not try and take a training approach intended for older children and use it with your son! Standard toilet training approaches do require physical, emotional, and physiological readiness that probably isn't present in your son.
If you opt for the "duct tape" approach, please be extra-super patient with him in a couple years when you are trying to potty train him. We spend the first 2-3 years training children that they *must* use a diaper. Then we abruptly change the rules on them and wonder why they get confused!