from chatGPT:

It’s a viral meme / slang term originating on TikTok and other social‐media platforms in 2025. Parenting Patch+3Wikipedia+3chicagoparent.com+3

The origin traces to the song Doot Doot (6 7) by Skrilla, where he raps the lyric “6-7”. Wikipedia+1

The phrase was further tied into edits of the NBA player LaMelo Ball (who is 6ft 7in), making the “six seven” number visually and memetically catchy. Forbes+2People.com+2

According to sources, “six seven” doesn’t have a clear, fixed meaning. It’s less about the literal numbers and more about an inside‐joke, slightly absurd vibe. chicagoparent.com+1

One description: it’s used when something feels odd, “off”, or you want a quick reaction that signals “huh, weird” without fully spelling it out.