A play on of "beam me up, Scottie" which is a popular startrek quote, and pm (private message) me. It's used to ask the person to clarify the "tea" in private messages, but it can also be used as a way to indicate you two should talk in pm in general.
Note: a shorter, cuter, version is "peem me up"
Jessica: I have this gross story about Debbie... Only telling close friends tho
Close friend: peem me up, scottie. im ready to hear it