...my dd (just turned 6) has had the habit of rubbing herself on the edge of chairs etc for a couple of years now.
What started as her way of avoiding going to the toilet (she used to do it when she needed a poo but had constipation) has now turned into basically habitually humping the chairs at any given opportunity as well as the edge of the bed or even the floor and it IS habit - she says she does it now just because it feel nice.
Well of course I understand and empathise with that but I have tried my hardest to explain to her that this is private and yes, by all means, do it if you want to, but do it in privacy in your own room, but as I say, it is clearly habit as she does it without thinking but it is CONSTANT.
As I said, I've tried to explain, I've reasoned, I've tried to interrupt and divert I've even told her off, all to no avail.
What would you do to stop this before it becomes a real ishoo as she gets older?