Your sorta right I should qualify that with "Spergs like Phil" Phil is on a part of the spectrum that has mental focus as a stumming activity. The ones you are talking about are on a differnt part of the spectrum that tend towards more Autistic end of the spectrum. Phil is on the end that's not mentally able to really understand the loci of focus he has but it does somthing in his mind that let's him focus for a bit.Er... not so much. Spergs can and do stim when they get excited, but it's usually a thing restricted to kids in those cases. Mainly because unlike full on autistic kids, spergs can on some level learn to extinguish stimming activities or channel them more positively. An example would be going from flapping arms to tapping the foot instead.
Though I would not be shocked if Phil does it for attention more than just being excited.
For example Phil loves statistical data, he's not really able to understand it but he's able to parrot it and make up data for Autismlatrina that to him looks right but he isn't able to take say a statistical norm and then fit it to his own imaginary data. I know there is that saying "There is Lies, Damned lies and Statistics" but that doesn't account for his lack of population leveling in statistics like population growth, citizens under arms sexuality demographics etc.
He loves maps as it allows him to apply that data in levels of detail he likes i.e. the way we know every postal code in the land but nothing about the regional dish of the Yoai (other than dick dicks), we have an extiveive list of weapons and millitary ranks and honours but we don't know the names of news papers, we know that there is a extensive road and rail network but we don't know the livery of a single rail or bus company, We know it would have in some areas a population density roughtly that of london in some areas but massive areas of nothing that include major citys that have police forces that are roughly 10% of the local populations.
The numbers faciate him but he hasn't got the comprehension to understand what those number mean.
The closest he comes to physical stimming is his Self Bondadge at times and that's mostly for the hugbox effect, and he doesn't do that much any more apart from when he wants to take a edgy photo. For example he thought he would prove us wrong posting pictures of himself in a Harness 4 weeks post op after we said it was a bad idea, and when he's ball gagged himself or when he figged himself with jordman present.
When he says he bounces and squeeks etc that's purely for attention and in the hours of video we have of him, and all the 1st hand encounters we have with him it has never once been mentioned.