I've seen this question answered before and the explanation was that small flaccid penises imply a proportionally large change when they become erect. While an

I've seen this question answered before and the explanation was that small flaccid penises imply a proportionally large change when they become erect. While an already large but flaccid penis would proportionally not change so much. Greeks considered the difference between the size of a flaccid vs erect penis a sign of masculinity, and therefore tended to use small penises. What's more glorious than knowing that the flaccid retracted penis of an amazing athlete will grow 4x when required (which is plausible). A larger non retracted penis wouldn't grow so much proportionally.