Just… being lazy. Like, the clothes are washed and dried, but they stay in the basket and never get put up. I put chores off a lot. There’s a certain anxiety I have about stuff, like I’m worried it’ll take forever or take a lot of effort. It never does, and it always works out better, but that anxiety stops me every time.
I was able to stop by teaching myself classical guitar. Suddenly there was a reason to have nails and it was easy to stop. I guess it's similar to the other guy having nail polish. Find a reason for yourself to have fingernails instead of simply trying to stop biting them.
Counting my toe flicks. I would flick my big toe and index toe up and down, alternating between left foot and right foot, while counting how many times I have flipped. I don't do it for a long time, mostly up until 20 to 40 counts. May be it's some kind of coping mechanism that I used to do when I was young but it somehow stucked.