Stands for Married-2-Kids-Philia.
A sexual deviance of women usually close to 50, seducing men who are married with kids, usually 2, and lead them to perverted behaviors.
She: "Hi, would you love talking about Middle Ages architecture?
He: "Wtf, what kind of perversion is that?"
She: "Come to my home, I'll show you how fun an art historian can be"
He: "My wife and my 2 kids are expecting me"
She: "Mmmh, don't tell that to me, you make me horny"
He: "Oh I see, you suffer from m2kphilia... I'm coming..."