Post pumping, between 30 to 60 minutes under a "restrictive" blood flow where the blood is allow to exit the penis in the interval of 5 minutes or so. Constrictive is when the blood does not or cannot leave the penis. This can result in a deadly outcome.
If you want to keep going after the 30 to 60 minutes post-pumping routine, you can do it all day long. It may be quite taxing on your time to need constant readjustment of the penis ring. The ring can bite into the skin and lower tissues after an hour or so.