It usually flops. Only twice I remember retaining my hard-on after coming. Once Iwas 20, I was fucking my girlfriend and came hard, then just kept on thrusting. We both were surprised I could do it. I went up her for 15 more minutes then came again. Once in my 40's but it's rare.
Generally it will stay hard for a bit if I am in her I will keep thrusting for a bit and then stay inside as I don’t like to rush out then I will slowly remove. My fwb will stroke me as I lay next to her and we both recover. Sometimes if I am still har and we both are up to it I will renter. Last friday my fb gave me a fabulous blowjob after I ate her and made her cum a few times. Then I fucked her as she came twice. After she blew me and I came she kept stroking me and then held my cock in her hand as I stayed hard. I am 62 and maintain good shape and health in order to fuck as much as possible lol.
Last week when I came I pulled out and laid back on the bed. My partner laid with me and fondled my cock but it was spent and needed a good nights rest. But some 6 month back I came 4 times in a row in about 40 minutes. Didn't pull out. I just restarted the thrusting once I caught my breath and remained erect until the last cum. That did it for me. The difference might have been that I was pretty high then and it seems that when I am high I can maintain hardness after cumming.