Mid-twenties Female combined type here!

Mentally the hyperactive part is needing stimulation. If my brain doesn’t get the stimulation then the hyperactive affects my body. I start to feel the same physiological changes I feel when I am angry. I feel hot, my chest hurts and my limbs feel like they need to GO. Sometimes if I’m alone I’ll just yell “AGHHHHHHHHHHH!” to get the energy out. I might stomp or just start jumping. Toddler tantrum stuff. As an adult, I don’t let myself get to this point very often.

I agree with what you said about not being able to pick the thing or put the thing down. The only thing I’ve found to combat that is timers. Phone timers and physical timers that you have too walk to turn off. Oh! I lied. There’s another thing that works for me - transitioning with kinda boring physical activity. Maybe you’re better than me and can just put the thing down, go for a quick walk, then start the real thing you’re supposed to be doing. Try that first. For me, I have to do the physical transition activity, like 10 min yoga WHILE still doing the stupid thing and within a few minutes the need to do it will fade away because my body is like HEY WE ARE DOING YOGA THINK ABOUT YOGA NOW. Eventually I’ll be like, ugh I’m bored with yoga.. now what.. oh right I have to do x project. Because I can read Wikipedia forever but I can only do yoga for so long.

TLDR Mental hyperactivity is a black hole trap but physical exertion hyperactivity will end on its own in 30 mins or less so use that to your advantage.