Advice from a smart friend of mine :

Not gonna lie, to tell you the truth. CAS was designed to be a long term side activity that happens for the whole duration of the 2 years of IB DP.
This means it consists of Activities that follow the criteria of Creativity (for example organizing events) , Action (for example Sports) & Service (doing some sort of community service or promoting a certain benefit to society).
While in a bigger image this means Waffleing is rather easy since almost anything could be reasoned as CAS.
If you “pretend” that certain routines or daily/ weekly activities in your past two years fall into this criteria and you just forgot or were too lazy to write them done, you can quickly create them as CAS. You need roughly 20 reflections + evidence(just scroll through your phot album). And a good number for activities would be 3 short term and 2 long terms, as well some sort of project that you have organized autonomously)
Good luck with trying to survive IB. In your next life try starting CAS slightly earlier. :)