almost non existent when I was younger. late 50's now and it takes awhile. enjoy it while you can young men!!!
I use to cum and not even go soft, grind, pound on pussy, cum again. take a 5 minute break and ready to go again. I could almost "will" myself a hard on. my gf, now wf, used to snap her fingers, and say "up" as a joke. the funny part was in about 20 seconds, I was rock hard. "simply amazing" was a compliment she gave me a lot.