well in short.. you dont have to "earn" a christmas leave period unless there is something really big I haven't been aware of.. its pretty much given out and expected of you to take it
while waiting for your next course ... it all depends. probably some sort of PAT platoon if the waiting time isn't that bad.. if it's a bit long maybe something with the home unit for example my friend while waiting for his AVN course got 2 weeks of OJT in his home unit.. they mostly acquainted him with the planes and electronics and basic aspects of his job and daily work life.
All depends what they want to do with you.... want an example? I'm heading to Borden on 05 Aug. I was under the impression (and I think I will but still) that I was going to do SQ there. Now they don't know. If I do do it, it also may be in Meaford, Valcartier, Wainright, Gagetown .... not Borden like originally thought. In basic terms I was told that "Borden will decide what to do with you once you arrive in Borden, how many courses are running, and what they think is best to do with you"
Hope that helps somewhat