How have you experienced bad men's anatomy?

We have all seen posts of men not understanding women's anatomy. How have you experienced this the other way?

For instance, My wife confidently told me that men who jerk off a lot actually stretch the skin of their penises permanently. If that were the case, mine would be looped around my waist.

Yes, I am aware of Jelqing, it doesn't work. That is not what she was referencing.