What is PCT?
PCT is "post cycle treatment."
This is simply put, the process where you get your natural functions back in order and working. Normal PCT includes a variety of all or some of these things: Clomid, Nolvadex, Clenbuterol & HCG.
When your PCT starts is dependent upon 2 things: what you were taking and how long it was since you took it. For instance, if you were using test (which you should have been) if it was a test with a long ester attached, test-e, cyp or sust, PCT usually starts 3wks after last injection. Some will begin HCG treatment a little sooner then that around 10 days after last injection, but Clomid or Nolva or both begin 3wks later. If you were using shorter esters such as test-prop at least the last few wks of your AAS cycle, PCT could and should start immediately after last injection.
As for training after cycle, you shouldn't be trying to go as buck crazy as you can while on cycle. Your intensity should still be very high, but volume is usually better at a slightly less amount then if you were on cycle.
Another note, a lot of guys experience not only a decrease in muscle size but an increase in bf as well once a cycle is over. For one, many let their diet go to shit after a cycle causing their cycle to be worthless. You should be striving to eat at least fairly clean and several meals per day whether you are on or off-cycle, but when you go off, I think you should be even more concerned about this, otherwise gains will dramatically disappear. Understand that once you come off cycle your body will be pumping cortisol out the butt, so it's important in my opinion to eat as clean as you can to minimize the damage, but to eat enough to maintain and feed the muscle you have gained while on cycle.