The term is used by a married mangina cuck who is raising a boy, that isn't his. Sometimes used by 4chan crowd to make fun of cucks (it was featured in "He Will Not Divide Us" Season 1)
A: "I see you got married. But who's the kid?"
B: "He's my wife's son"
A: "Oh, so a bastard child, huh?"
B: "I wish you didn't call him that."
A: "I guess it's better to be raised by a cuck than a single mom..."