Did you hear it from a movie, or from the TV show Kim's Convenience? From what I can find, the first person is a waitress, and she is offering for the customer to look at her *actual* box of tea. The customer, a man, says he would love to check out her box. Box has a slang meaning which can refer to the female sexual organs. Read more: https://www.springfieldspringfield.co.uk/view_episode_scripts.php?tv-show=kims-convenience-2016&episode=s03e05?

thank you guys 😊. actually I've heard it from a movie.

If you weren't talking to this person about an actual box, it might only be a slang word with a sexual subtext. It's definitely level beyond flirting and cannot be appropriate.

I agree with Sydney. I think it goes way beyond flirtatious

I could be wrong since I don’t know the context, but if someone said that to you they were probably being crude and inappropriate. “Box” is a slang term for female genitalia.