Forgot name

Heyy does anyone know what I'm talking about?? The only thing I like remember from it was that it was a bl and I think it was sub/Dom?? Or something like that, the only part I really remember is that when the sun said the safe word the Dom went into like a state(?) and was like worried. Then like flashback I think to when sub was talking about someone saying when you say safe word the Dom will feel like they did something wrong and hi into a state of worry. Something like that...
Idk it just came to my mind but I can't find it