lately, i've kept my erection for about 2-3 minutes after ejaculation, and it slowly goes flaccid after that period of time. i guess i should note that i have been doing more pc exercises than i used to; maybe this has helped, maybe not.
unfortunately, though, my cock isn't as sensitive after cumming as it was before cumming. i have been able to stroke it enough to cum again, but it doesn't feel as pleasurable to me as the initial orgasm. in order to feel another good orgasm, i have to wait at least 15 minutes, and by then i'm flaccid.