Almost 6 year old not toilet trained

My stepson will be 6 at the beginning of February.  I have attempted to potty train him since he was 2 1/2 with great success, but he would return to his mother's and come back having continual accidents.  Over the summer, I started a reward chart and he did not have an accident for 2 full weeks.  Then he went with his mom for a week and came back having accidents again.  No peeing accidents, only poo.  The frequency has grown and he sometimes has up to 4 accidents a day.  I'm not saying it's her fault, it's just that we've tried everything and all he says is "He's sorry".  We have heard not to punish children for this, etc., and don't, but it sure is frustrating, knowing he is well aware of what he needs to do.  He has quality examples, as my husband and I have 2 other children together that are 3 & 4 and are fully potty trained.  At his other home, he has 5 & 7 year old sibilings that are also fully potty trained.  He's in kindergarten and after school care and essentially, because it's a requirement the child be potty trained, they leave him in it (which my husband will be discussing with them shortly, as poor clean up is creating a rash).  He does not wear a diaper to bed, hasn't for several months and does not wet the bed either.  Any help is appreciated!

[PhilAP]

Checking several sites on this topic I'm struck by the frustration expressed by parents and sense the stress the children involved are suffering.  Based on what I learned in an enlightening collage course on behavior, during a couple of generations of family experience, and research,  I would like, as a lay person, to share some observations.

There are several reasons for panty pooping and wetting including revenge, revolting (pun intended), claustrophobia - not liking to be closed in small rooms, especially with a large stone mouth that can swallow a whole child, or a physical condition.  

I believe there is another seldom considered reason - are you ready for this - ITS FUN!

One of the first things children independently master is bowel and bladder control. Some children, usually the smarter ones, master this function earlier than others and it may not be noticed by parents. The shift from involuntary to voluntary control is subtle. In an another wise boring time, being able on their own to relieve pressure and even pain by conscientiously spreading the legs a bit and filling underwear, and the resulting relief, pleasure and feeling, can rapidly become addicted behavior, even imprinted. Toss in some erotic feelings (oh yes, your child has them) and an underwear fetish may develop (or may not).

"Fetishism" is characterized by sexual urges and sexually arousing fantasies generally involving non-human objects.

To determine if panty pooping and/or wetting is a behavioral addiction requires some detective work.  
1) Hiding soiled underwear is a sign your child feels guilty about causing problems, but not enough to stop the behavior.
2) Washing soiled pants is often seen as way to continue this behavior, eventually in private, without inconveniencing others.
3) An affirmative answer to any of these questions, asked in a relaxed and non-event environment, is a positive clue:
       A) "Is going in pants more fun than using the toilet?"
       B) "Do you think I would enjoy going in my pants?"
       C) "Because you go in your pants a lot is there a special type of underwear you would like?"  You might be surprised to receive an intelligent discourse on stretch, absorbency and leg band tension.  Your child is pretty smart!  Otherwise he or she wouldn't be in this mess (intended).

If you think you are dealing with addicted behavior, than you should make it clear that:
1) This type of behavior is different, however it is not uncommon or unhealthy if proper sanitary practices are followed.
2) Because most people don't understanding panty pooping it must be done in private, not in public, or in school, or when guests or playmates are around.
3) Pooping and peeing in public will influence how you are accepted by others resulting in devastating social problems that will effect your family, life and career - forever.
4) That this urge to poop and/or wet panties will start to go away as you get older and find the extra time and effort involved is not worth the results.  (It can increase if under stress or bored.)
5) And, "By the way, don't spoil our floors or furniture!"

Sorry, you can not beat an addiction or fetish out of a person.  Seriously harassing a young child can cause bonding stresses that may lead to RADish behavior. No, that's not something to eat. "Reactive Attachment Disorders stem from problems in the parent/child relationship in the earliest years. When infants and toddlers should be learning that their needs can be met by the people they are dependent upon, they learn instead that it's not safe to trust others - that to be dependent on others is not worthwhile. Kevin Kennedy, Ph.D" .  Shipping feral children to Russia is not an option for most folks.

It is important to not make this addictive behavior a bigger problem than it really is. Remember, this is not your child's fault! You're the one that missed or messed up the critical potty training window.  
1) You are going to have to accept the problem's existence, control it in low stress manner, and it will eventually go away. Or more likely be repressed.
2) Have pants available. A clear place they can wash and dry. And make sure they know you are available to discuss anything, anytime.
3) When shopping let them pick out their underwear.
4) Put some interesting magazines in the toilet.
5) Try to influence event frequency, maybe "every other time" progressing to "once a week", etc.
6) When they clearly stopped doing it in public try to have more friends, theirs and yours, around which will encourage more toilet use.
7) When mature enough explain the reasons behind this behavior, and maybe your role, and emphasize that it is not un-common.  Developing a good self image is important. Children should not think they are some kind of a freak.

Good luck finding a doctor, any kind, that isn't baffled by this "serious defecational defect". Their revulsion with messing around with crap overcomes logic. Your child will have a happy and successful life, if not with some professional help, then with the counsel you provide. Post if you do locate a competent professional who works with children's addictive behavior and fetishes.

Please do not use sugar to try to change behavior. I think addicting kids to sugar should be considered child abuse. I would rather be with a healthy well adjusted adult, who may occasionally enjoy taking a secret dump in a pair of drawers, than a sugar addicted slob, like you ones you've seen blocking the aisles in Wal-Mart. Usually leaning on a large cart full of carbohydrates.