If I'm talking to someone at a party, can I suddenly say: "So, what do you say, is it time we hit the dance floor?" Is the use of "what do you say" natural in that context?
Could I also use it if I have just asked someone if they want to do something but they are hesitant, so I ask: "What do you say?"?
"What do you say" invites someone to give their opinion.
What do you say to hitting the dance floor?
That's a great idea! / I don't really feel like dancing.
Your first example is fine.
The second seems strange. You've asked them, and they are hesitant (so they've espressed their opinion) but you are asking again, when you already know what they'll say. It would probably be misunderstood as "What did you say"
Do you want to dance?
Maybe later.
(?) What do you say?
I said, "Maybe later"!
