I like to pull the corner of my phone case off and snap it back on

Not exactly my favorite, but my most done is biting/peeling my lips.

Stretching is probably my favorite. Like those good ones after waking up

There’s been a song stuck in my head for as long as I can remember (decades) that only comes out of the recesses of my brain when I’m alone, and I hum it over and over. Usually this is during driving or focusing on coding. Kinda frustrating that I don’t even know if it’s a real song or just something my brain is doing for fun. (It sounds a bit like the civil war song, When Johnny Comes Marching Home, I guess?) I’m too self-conscious to do it around other people.

• jiggling pectoral or glute muscles (usually to music)
• opening and closing the lid of an inhaler
• grinding the folded tags in clothing
• stroking beard
• peeling top layer of skin off finger nails
• plucking overly long eyebrow hairs

As an adult it is a mix of leg jiggling and rubbing my finger nails against my thumbs. As a child I used to tap out rhythms with my heels and toes, much to the chagrin of my teachers and classmates.