The hot seat/cold seat concept is how I was taught to play the two-up position (although we didn't use the cool terminology
). The cold seat person is responsible for all lobs to his/her side, plus lobs that land within 6' of the baseline on the hot seat side. There really doesn't need to be a lot of verbal communication because everyone knows who is supposed to get what balls. And it forces your opponents to hit really good lobs if they want to stay in the point.