Plámás. Pronounced plaw-maws. It's an Irish word that mostly means "gently placate" or "smooth talk" but usually I would use it in the context of placating someone who's behaving badly.
e.g. Don't plámás that eejit. You'll only encourage him.
I don't think it directly translates to English though someone with better vocabulary may correct me.
Yes indeed it's very close, but in my head it's slightly more active.
Let's say a child is having a meltdown and the parent is trying to (incorrectly) placate them by giving them an ice cream. That would be plámásing. I feel like it actively encourages the bad behaviour rather than being more neutral which I'd consider "humouring".
Onomatopoeia, it's a fun word on it's own, but I love the while idea of it. Especially in other languages, like the million different words for dog barks.