In the earlier series, the exterior the Carrie's apartment was another apartment block (in one episode we see a couple having sex through this windows). In later series, the exterior changes to the street outside and the other apartment seems to have moved. See more
You men have no idea what we're dealing with down there. Teeth placement, and jaw stress, and suction, and gag reflex, and all the while bobbing up and down, moaning and trying to breathe through our noses. Easy? Honey, they don't call it a job for nothing.