Hourglassing but no pain or curvature

[Mandem29]

A few months ago I had started experiencing some hourglassing around my penis. It turned out this a symptom for Peyronies and I had expected to start experiencing some
Pain and curvature but so far none of those have occurred. Also regarding the appearance of the hourglass, it would only appear when urinating then my penis would go back to its regular shape. It would appear like that again during the same situation and other times where I wasn't peeing and it would go back to normal after a few minutes again. Can anyone explain why this is happening?