"I'm going up the road to hit up some Maccas action" refers to an activity whereby McDonalds will be purcahsed and consumed in the near future.
When this use of "Action" is combined with "Relax", we arrive at Relaction, which is a noun/verb combination suggesting an activity relating to the act of "Relaxing".
E: Oh nm man I'm gonna hit up some relaction later on, probs get a pizza and watch some tv.
I: Coo', I have an essay due but I can't wait for some relaction this weekend.
E: Hells yeah!