My ds is a terrible terrible fidget. We always talk about it at parents evenings because it drives his teachers insane. It doesn't seem to distract him, just everyone sitting around him. We have tried a few things to keep his hands occupied, but they have all been lost or ineffective really. However at our new school the OT attached to the school who he is going to see for help with his handwriting has given him a "fidget" and it really seems to have worked. It is a fiddly thing that fits on his pencil. He likes it, and the teacher says that although she has had to persuade him not to wave it around in the air it has really made a difference. So I thought I would share this with anyone else who had a similar issue. They look like this: www.fidgets.net/ Mostly available in the US, but this website has them for the UK: www.specialdirect.com/Product.aspx?cref=TTSPR821427&rid=174&cid=19
They fit on nice and tightly. He also has a squishy thing for better grip (I expect he fiddles with that too). The SENCO in the UK tried him on all sorts of things (stress balls, those twisty things that you can snap in different ways etc) but none of the really worked, and the teachers got very distracted when he continually flipped rulers and stretched rubber bands... He has a high need for sensory input.