It never ceases to amaze me how much utter claptrap is spoken about this subject. Flaps being "ripped off"? Perlease....
There is only one correct answer to this: Look in the POH for your specific aircraft (not just any old 172's POH or one of the generic "pilot's guides"). Obey the limitations according to the actual words in there, not some rubbish that somebody once told you, or something you read on the internet somewhere. And don't exaggerate what it says in the POH.
Typically, the POH of
some 172s specifies that you must not slip with
full flaps (but check the wording in your specific POH).
This has, somehow, been twisted and distorted into:
- Do not slip a 172 with any flap
- Do not slip any 172 at all
- Do not slip any high-wing Cessna
- Just to be on the safe side, don't slip any aeroplane.
- If you do, the flaps will fall off and your willy will turn green
- etc...
- etc...