There is a common misconception that this term refers to any male because it references the male organ, but the more important part of the term is "swingin'." That is, not just any man, but an especially potent or imposing man. Hence, a badass.
2) A: "Did you read that new Judith Butler article? She totally destabilizes the regime's reinscription of normative typologies."
B: "Yeah, she's a swingin' dick when it comes to critique. Also, stop talking like a d-bag."