37 here. Have pounded many 20 year olds into asking for time outs. I masturbate (and cum) while they’re still catching their breath. I fap plenty, before, in between rounds, and after rounds.
And I know a few other guys like me. You *did* say some, so i’ll give you a pass on that.

As for the sex doll, I HIGHLY recommend that, for endurance and stamina. Get one of the training tengas/fleshlights, turn on some kick ass porn, get plenty of lube, and fuck the shit out of that toy. Once you come, keep going! Slow down a bit but keep going. Eventually, the oversensitivity goes away, and viola! You’ve just learnt how to go multiple rounds. Practice makes perfect; eventually you get to the point you can keep going multiple rounds like this.