Anger brought on for no environmental or emotional reason, but instead arbitrarily from an excess of androgen in the body. Terms as such because it is often exitbited by those who use steroids incorrectly.
Testosterone naturally feeds the territorial pride instinct in man (both men and women), so roid rage is most likely just nature misguiding an individual to attack when there is no stake to claim or preserve.
When Bill toyed around with intramuscular testosterone abuse, it made him feel like a god, but caused him to lose his girlfriend after he hit her during a fit of roid rage.
Someone who takes performance-enhancing substances such as androgens, testosterone, steroids, and such and becomes prone to sexual stimulation as a result, as well as forcing themselves on a potential victim, likely becoming angry if they resist, even more so prone to anger due to the substance-abuse.
Olaf: You heard about what happened to Arnie at the stripclub?