What do we learn about Offred`s evenings with the Commander?

Offred continues to meet the Commander in his office at night. They develop a system of signals so that Serena will not realize what is going on. If Nick is polishing the car hatless, or hat askew, the Commander wants Offred to come see him. Although the Commander does not make any further physical advances toward Offred he allows her certain liberties forbidden to others; they play Scrabble, and he allows her to look at an old copy of Vogue.