S.G.
Both of my kids would wear underwear or go bare all day at home, and then ASK to put a diaper on so they could go #2. This went on for awhile, about a month or so. Then my son started sitting on the toilet, and I would sit in the bathroom with him while he went (initially, it could take ah hour or so!!). My daughter preferred to drag the little potty out into our family room and sit there naked as a jaybird and look at books. Like so many things in parenting, eventually it will just work itself out. Sounds like he's well on his way. If he wants to wear a diaper at bedtime, I vote let him.