I'm as serious as dick cancer
When a guy says he's as serious as a guy who got cancer from a tiny noodle.
Guy 1: Are you serious? Guy 2: I'm as serious as dick cancer.
Guy 1: You're not even trying? Guy 2: I'm as serious as dick cancer.
Guy 1: You're telling me you’re not messing with me? Guy 2: I'm as serious as dick cancer.