Simular to the phrase "I dont give a rats ass" but for use in enviroments with under 3's. If you want to say "I dont give a rats ass" but happen to be in the crèche you can alternatively use "I dont give a rats left foot".
This phrase is also good around people that would willingly class themselves as snowflakes, assholes or English language Nazi's.
I dont give a rats left foot about all the times the process works, I only care about times the process does not work.