what is this song dance dance like your legs are on fire

That looks like “dance like your legs are on fire” by Joseph of Mercury. The line appears in a post promoting the song “nikki,” which matches your lyric fragment.

Quick scoop

• The lyric snippet you gave is most likely from “nikki” by Joseph of Mercury.

• The phrase is used in a promo caption that says, “dance like your legs are on fire”.

• If you were thinking of a different song, that line is the strongest match from the results I found.

Why this match fits

• The wording is unusually specific, which makes it easier to identify.
• The search result directly ties the phrase to a current music post for Joseph of Mercury.

• No other result in the set matched that exact lyric fragment as closely.

TL;DR

Most likely: “nikki” — Joseph of Mercury.