This episode is a great follow up from My Drug Buddy, especially the start where JD has to think of the perfect words after sleeping with his best friend and comes up with "Good job last night buddy". I think the writers did remember about the Jordan-JD "relationship" at the start of the season but decided to leave the "I've been stuck on four since Med school" gag in because it is a hilarious scene.
The rest of the episode was great too, especially the pizza being used as a clock and Dr Cox in therapy.
The whole episode is very entertaining and is a good idea for the show to just have the three episode relationship: hook up-relationship-after breakup. This episode is both funny and sad at the end where neither stands up and it is revealed that they both thought it would last. Switching back and forth to the first day is a very good idea and makes this episode a great one.