Men noticing their penis appears smaller during or after a workout may be seeing a temporary change in its flaccid appearance rather than an actual reduction in size. The phenomenon has recently been dubbed ‘gym penis’ online, with the terms referring to temporary retraction of the penis and scrotum during or after strenuous exercise. “It’s a normal and natural physiological response” – Cleveland Clinic urologist Dr Raevti Bole on ‘gym penis’