Most of my OCD revolves around counting so I have plenty of number issues lol.

Whenever I do something, it has to be a 4 or 8. Whether it's petting my dog, walking, even breathing, I count it every day. 1-2-3-4 or 1-2-3-4-5-6-7-8, it just depends on what I'm doing. If something takes longer in general, its 8; if it's shorter, then 4.
If it's really long I can count to 8 four times.

Also, when I'm looking at a number i.e. the microwave counting down, or a streetlight walk sign counting down, i have to keep watching it until it hits a multiple of five or 0. so if it's at 19, I have to wait until it's at 15 before I can look away. if it's 3, I wait until 0. And I can't even blink until it hits that number.

It's literally physically painful to not go to that number. I've tried to look away at a 6 before and I started feeling nauseous and dizzy. Same thing if I stop like petting my dog at a 5 rather than 8.

Also, when I'm speaking, I can usually speak fine, but sometimes some words don't sound right the first time, so I have to repeat the word three more times and if it doesn't sound right by the fourth time, then I have to go to 8.
It was so bad a few years ago, everyone thought I had a speech impediment.

2 is also an okay number. it's not my favorite but it still gives me some satisfaction when i do certain things.

so like if i have to crack my neck, i have to do the other side too to make a 2. and then once I start cracking my neck (2), I then have to crack all my fingers (10), my wrists (2), my neck again (2), my shoulders (2), my ankles (2), try to crack my toes (10), then my neck one more time (2) to make an even 32- or an 8 four times.

It's an entire routine. It's a ritual.