Meaning of "swayed approbation on our faces"?

Hello everyone. I am reading a novel, and I came across this expression. Could you please let me know its meaning?

We were all tasting his wine.

“Now try the other,” he said, proceeding to decanter the pinot into my glass once he saw that I had downed the sauvignon.

“Another small miracle.”

We all tasted, swayed approbation on our faces. Inky’s grandfather was staring at me. He suspects they’ve broken up already. He’s trying to feel her out before seeing if he can patch things up between them. I’m now definitely the one-too-many in this crowd. I should have called a cab. I’d be in the station and far away by now.

- André Aciman, Eight White Nights, Third Night

This is a novel published in the United States of America in 2010. This novel is narrated by the nameless male protagonist who meets Clara at a Christmas party in Manhattan. Two days after the party, Clara came to the protagonist's house in the morning and drove him to her best friend's house, who is the grandfather of her ex-boyfriend and childhood friend Inky. At his house, they are all tasting the wine he brewed.

In this part, I wonder what the underlined expression means.

I just cannot parse this sentence, so I cannot quite grasp whether "swayed" is a verb or an adjective here.

Also, I wonder what "swayed approbation" might mean.

Thank you very much for your help.