When a gentleman's phallus undergoes excessive stimulation causing the penis to become enlarged and swollen. To the degree where it appears to take on a red to purple pigmentation. Other symptoms include extreme sensitivity, additional girth, and the sensation of incumbrance in one's breeches.
Known causes: Hyper virility, vasodilators, and grooved Cerebrums
An absolute stallion of a man often described as an alpha or sigma male has been enlightened with such intelligence that he has been bestowed Plump-Dick.