BKCMS is an abbreviation for the
slang "Baap Ko Chodna Mat Sikha". It is used in reference to when a novice tries to teach an expert something.
It literally translates to "
don't teach your
father how to fuck", from English to Hindustani.
1.
Virgin son: Dad, you should ask
mom to give you blowjobs
Dad: Baap ko chodna mat sikha #BKCMS
2. Person 1: Bro I
aced my finals this week, you should study with me.
Person 2, who has been consistently topping in every class since the first semester: Baap ko chodna mat sikha #BKCMS