The two weeks of post-5s are for growth just like the other six weeks - only skip them if you don't want to reap the benefits of lifting heavy iron for a further two weeks.
Joking aside, for the two weeks of post-5s you either keep training with your 5RM loads or you continue to increment the loads a little further (to about your 2 or 3RM) and do negatives.
I don't think many folks do negatives - for certain exercises they are often impractical without someone to help out or unless you have access to certain machines. Dips and chins are exceptions; it's pretty easy to perform negs for these if you have a platform. Use it to stand on to get back up to the top position after each eccentric.
Instead of negs, another effective method to allow for a little more loading is to drop to sets of 3 reps. Stick with the same 5RM loads for the first week of post-5s (say 3-5 sets for a total of 15 reps). Then for the second week of post-5s try to increase the loads a little but maintain the total rep count. You may need to cluster reps after a few sets and end up doing something like this: 3, 3, 3, 2, 2, 1, 1. It's possible to keep this going for several weeks more if desired.
Another popular alternative for post-5s is to switch to Max-Stim style reps which are a very effective way to manage fatigue while lifting heavy iron on a regular basis. (Do a search for Max-Stim if you need more details on this method).
With all of this heavy stuff, do take care. Don't just push up the loads if you already feel that your form is starting to suffer. There is no sense in getting injured.
Hope that helped a bit.