Our 2 1/2-yr-old daughter's in the midst of potty training, especially w/ pooping. Sometimes, she'll go on the potty, sometimes, she'll go in her pull-ups - it's mostly a control thing that kids have to understand to let go of, and it also comes with maturity and confidence that they each have to deal with on their own, but each kid is different. I, too, let our daughter go naked from the waist down in the house, and she's only pooped on the floor twice so far. We tell her that she's a big girl now, and big girls go poop/pee pee on the potty. I'd suggest just encouraging your son to go on the potty, and have some potty books with you to keep him motivated. Bribing our daughter w/ "potty snack" has also worked. We give her 1 m/m for going #1 and 2 m/m's for #2. We also have a newborn baby girl, so we're just going with the flow for now...hopefully, our kids will outgrow this soon! Good luck to you :)