Turtling

Yup. You just slide it on like a sleeve for your dick.

Yes - just like a cock ring, only our rubber has the ability to stretch 10X it’s original size and retain it’s elasticity. Be sure to take a look at the suggested size chart to ensure a proper fit. With a sleeve or Girth band you want to have a mild amount of compression without being too tight.

In my experience I either stretch using a hanger with very light weight or light tension for 30 minutes OR jerking off for *awhile* right after your penis exercise. I think that at erect state, all the blood comes and fills the newly formed cells. This is of course my science.. But makes sense right?

What is the actual cause of turtling? Is their a medical explanation? Diet? Genetics?

Without sounding like a smart ass…. I’d say it’s because you’re human. Your penis retracts and relaxes based on two things primarily - surrounding temperature and any stress you’re feeling. Kind of like your eye pupils react to the amount of light available.