How to go about writing tics? I have tics but I never know how to write them naturally, especially cause I often forget I even have them. To me it's like describing blinking or something? But I of course want the character to notably have tics, even though my internal experience of tics isn't very noticeable to me? If that makes sense?
Jerk, California by Jonathan Friesen is a book about a character (Sam) with Tourette's syndrome, written by an author who also has Tourette's. One of the things I really appreciated about the book was that it described Sam's tics in a way that made sense with how they felt as somebody with Tourette's.
In the book, Sam's tics are generally described when they're relevant. Usually, this is either to show that he's upset/otherwise worked up about something or as a way to build tension within the narrative itself. Although it doesn't necessarily mean that Sam isn't ticcing otherwise, it came across as the tics being more noticeable in those moments -- which I felt was a nice touch.
Consider the following passage from the book:
I glance around. My muscles don't jerk, and I close my eyes. I breathe deep, and like the third runner who finally catches up, the overtakes me. Slowly at first–a hard eyeblink. But that's not enough; there's more that has to work its way out, and my teeth grind. Movement spreads to my shoulder, and soon my whole body springs to twitchy life.
Even without the rest of the context of the scene, the description of his tics is enough to convey how he's feeling in the moment.
In the more mellow portions of the book, his tics aren't generally described at all, which helps it to feel more calm.
Another thing I liked it that they're described in the same way as any other action or movement.
This is another passage from the book:
The class groans, Heather swears, and my shoulder jumps. My elbow knocks my textbook to the floor with a thump.
Although the author doesn't explicitly say that Sam is ticcing, we as readers can get that idea from the way it's described. Essentially, this is to say that you don't need to explicitly specify when something is a tic or not – your audience will generally pick up on it.
With verbal tics (Especially ones that involve speech), it can be a bit harder. There's a kind of balance you want to strike between showing the tics and still making sure that the dialogue is readable.
While discussing verbal tics that occur outside of dialogue (i.e. Not interrupting the character's speech), I'd suggest marking the tic as such through dialogue tags. Words such as "blurted" or "exclaimed" can imply an unintentional aspect to the speech.
You could also describe how the character is experiencing the tic themself (If it's from their POV).
This is another passage from Jerk, California:
"No thanks, Jace. I'll stay with Sam."
"Hah!" The word fires from my mouth.
I purse my lips and bite my swollen tongue, but my vocal cords are locked and there's nothing I can do. "Stay with Sam! Stay with Sam!"
If you're writing in the POV of another character, you could describe how it looks from their perspective. Though I'd be careful with this, as it can come across as mockery if it's not done well.
With verbal tics that do interrupt dialogue, be careful to ensure it's not too frequent as it can make it difficult to read. I'd also suggest using some sort of formatting to identify tics vs general dialogue.
An example could be: (Note: This is not from the book)
"You know, I don't think–hey!–that would be a good idea."
That said, you would have to establish that the character has tics beforehand (And, ideally, establish this speech pattern as such), otherwise it can look more like an interruption or something similar.
I'd definitely suggest taking a glance through some books about characters with tics, just to see the format that other authors use. There's a wide range of options out there and the book I referenced here is just one of many ways to do it.