Typically, this is something you don't want out of a child. My 4.5-year-old has been brushing his own teeth for about a year. The problem is that I can't convey to him to spit out the toothpaste. I demonstrate and explain and still he just swallows. Suggestions very welcome.
If your child is pretty good with competition (this won't work with kids who are sensitive about not winning things or who don't want to participate in competition) Have a spitting contest. I know, as you said, "not a behavior you really want most of the time" BUT there are times for it - you've found one.
Practice spitting watermelon seeds and things that do NOT taste good like his toothpaste probably does (explain this behavior is only for really special times like in the bathroom and adult condoned spitting contests).
Have a family contest in the backyard.
Then, when you know he CAN spit (because now he has gotten help from you, siblings neighbors etc and shown you he's pretty good at it right?), you can use water swishing to help him have enough "stuff" to spit when brushing his teeth - just don't use so much you negate any effects of ongoing protection.
You might also try making a game out of it like, how long can you brush without swallowing OR spitting? Brush together and see who "wins". If you aren't having a contest, just encourage him to spit more often than you would yourself, use an egg timer to have him spit every 30 seconds or so. . . Make it fun and silly, he'll laugh, you'll laugh and maybe he'll get it.
In addition to practicing with water, what helped us was to use a 'big kid' or 'adult' toothpaste - one that tasted of mint.
We found that the little kids bubble gum ones he wanted to eat, but the minty stuff he wanted to spit out. If you check, you can see that the kids toothpaste actually have the same fluoride content as adult ones - at least the ones we were using.
We ended up using Tom's wicked cool children's toothpaste. It is not overly strong, but it doesn't taste like candy (makes his breath fresher too).
It also helped explaining that there was stuff in toothpaste that was good for your teeth, but not your tummy, so he had to spit.
(If worried about the fluoride content of the toothpaste, talk to your doctor or dentist about a good one to use)
My son has recently started doing this all by his own, just because we did it (in a typical 3yo way he did it way too often). Children under 7 should only be using a pea-sized amount of toothpaste to minimise swallowing, so I wouldn't worry, I'm sure they will adjust in their own time. Brush your teeth together, and just keep encouraging them every time you do it.
My 16-year-old son, who is a nonverbal autistic, has spitting problem since he was a child. We tried showing him every possible way to spit out anything that is in his mouth, but he wouldn’t spit out. When it comes to food, he would be gagging if it is just a little bigger than a bite size. Still he would not spit out.
One thing that helps with brushing teeth is to put my finger in his mouth to prevent him from swallowing. At first he bit my finger, but the next time around he would not bite again. After finishing up brushing teeth, with my finger still in his mouth between his teeth, I take a cup of water and pour it in his mouth and then lower his face toward the sink and allow water to flow out. I repeat this last step few more time until the water coming out of his mouth is clear and no more tooth paste in his mouth on on his tongue. That is the best we can do to help him. He wouldn’t do this on his own.
My son does this, or on occasion he puts his head over the sink and opens his mouth watching the water just fall out, same effect but different concept. Although you could practice outside, or in the bathroom sink, with a cup of water and do more "modeling".
I think the whole swallowing reason is why children's toothpaste, at least in the US, is made to be swallowed since young kids don't always grasp the concept.
I'm unable to answer the question for you, but I wanted to give some insight of why I'm interested in this post.
I am a female, 23 years old, and still am unable to spit. My family and my siblings have all tried to teach me, especially around the age of graduating toothpaste and swallowing watermelon seeds.
I attended speech therapy during preschool age; I don't think spitting was focused on, as speech therapy was focusing on the fact that I wasn't talking at all!
When I brush my teeth, I use a hand-towel up close to my mouth - I hate mint and anything remotely spicy. But I do know that I HAVE to brush my teeth.
Two facts about me: Of course #1. Can't Spit. #2. Can't blow up a balloon. I have found others with balloon problems, but haven't found spitting problems - but probably that's considered rude for grown-ups to ask about. And of course, who doesn't spit? :) Mouthwash; rinse; gargle = no-go. If something goes too far back - it gets swallowed.
Just thought I'd share a tidbit, of whoever is looking in the same lines of information.