A K Card is what you have if you have not kissed anyone yet, after your first kiss, you lose your K Card, the person who you gave your first kiss to willalways have your K Card
I lost my K Card when I was 7 years old, I wish i could get it back but she will have it forever
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi