Can sex be used as a form of PE?

Good question. I used to edge and masturbate for an hour or more a day (almost everyday) for 10 years, and I didn’t gain much. I think if you have already reached your natural potential (max out your erection quality), then you will need additional force to bring further gain (ie. stretching, clamping.. etc).

So for someone who is not really sexually active and have not done PE in the past, then regular sex (and longer sex like 30 min+) should produce a bit of gain. And it’s probably mostly gaining one’s full potential.