to dwell on, to keep thinking about
J'étais dans ma chambre, en train de ressasser l'opportunité manquée.
I was in my room, brooding over the missed opportunity.
Si je ne l'avais pas retrouvé, j'aurais passé la journée à ressasser.
If I hadn’t found it again, I would have spent the day dwelling on it.
— Aquarius (2016)
Je pense que tu as tort de ressasser ces rêves.
I think you're wrong to keep dwelling on these dreams.
— Harry Potter et la Coupe de feu (2005)