When a man suddenly gains enough cocky bravery to face a dilemma or challenge which he was previously afraid to do.

Such a feeling simulates the results of one's testicles expanding due to a tumor, which explains the combination of the words "Man" and "Cancer". With his newfound "big balls", a man will stop being a whiney bitch and achieve his goals.

One experiencing Testicular Mancer will gain a short term badass attitude, shortly followed by sweating, crying, and proclaiming "Holy shit, did I just do that?!"