Yeah, it’s totally safe, but remember to keep several hours in between, after a PE session and before sex, just to make sure that you have your erection strenght. Exercises can exhaust your penis and might cause very short-term temporary impotency.
"Be aware that there are several schools of thought here as well. Some seem to go with the hard and heavy approach. The sessions are brutal. You can hear them talking to their dick: You better grow mofo or I will punish you even harder tomorrow! Others seem to favor a more tender approach. Always listening to what their member is saying while massaging it gently and singing to it with a soft voice. If it is moody and not happy with new behavior, they always listen and are very understanding."