My son is 3 and has been potty-trained for over a year.
This is just his way to show you,he thinks this is a fun way to get you to run after him more.
first thing to do,buy some very cheap cloth underpants,it really does not make any difference where you get them,and also buy about a 1/2 dozen pair of plastic pants in his size,next time he goes in them, don't hurry,but take him straight into the bathroom and strip him down in the bathtub,then telling him that he would be playing now,if he had only used the bathroom instead of his pants,and be washing him down slowly with Cool,(not cold) water.
Be consistent and he should be ok in a couple of days to a week,depending on just how stubborn he can be.
Don't worry,this is normal,most actually would not stop at nap time only.
Please keep us up-dated on what you try and his responses.
Give him the week and we will see if anything is sinking in.
If not,we do not want to go back to pull-ups as they are nothing but glorified diapers and kids know it,they just give him permission to use them as such.
If you think he is going to be to stubborn,be sure to get the plastic pants as we will start to use the 3 strikes method,it is a last resort method I have used for years,and there are very few that last long with it.
Thanks so much for your help. I came back because we are still having problems. Can you tell me what you mean by plastic pants? Do you mean the elastic waistband athletic pants or something else? How does this help? Also, what do you mean by "three strikes" method?
Sorry to be so long in getting an answer to you.
Plastic or as we used to call them rubber pants are the pants that go over diapers,cloth training pants and regular underwear when needed to help contain accidents and keep clothing and furniture
Although I believe the plastic pants and three strikes method is an effective method, in this particular situation, I'd personally go ahead and put your ds back in pull-ups for naps.
Since the problem began right after your baby was born, to me this sounds like a situation of stress and/or power struggle -- even if your ds isn't consciously aware of it. In fact, even positive stress (like getting a new/different teacher at preschool, even tho' they are well-liked) can create potty training disruption for a child.
I'd personally rather not set up a situation designed for failure, mess and stress, esp since your ds is still young enough that if he wears a pull-up at naptime, it shouldn't be a big deal.
I'd just matter-of-factly let your ds know that since his body doesn't seem to be able to stay dry at naptime that you're going to let him use pull-ups again. It's not a punishment, it's not a reward, it's just something that is going to occur. After several weeks/months, you can try again.