Tuvan Phone Call

A phone call in which you choose your words carefully in an attempt to maintain a coherent conversation with the person on the end of the line while giving a completely different impression of what the conversation is about to anyone standing next to you. Usually involves more than the usual number of pronouns.

From "Tuvan Throat Singing", where you sing two different notes at once.

I had a Tuvan Phone Call last night with my girlfriend. We went on for half an hour and my Grandma had no idea we were having phone sex.