For the first several months when I first started having intercourse, I would cum really fast, usually within 30 seconds of penetration. But I would stay rock hard and cum again in 3-4 minutes. After that one I would still be hard( but not as hard as I was ) and could go for maybe 10 minutes before cumming again. Usually that did it for me. Once after the 3rd time my girl gave me a BJ and I got really hard again, re-entered her kept going but couldn't cum again. She came a few times that day too. I must add I was only 18. As a side note, For my thirtieth Birthday we went to a motel with a nice hot tub in the room. I came 11 times in 24 hours. Never before, never since. ane we were both sore for days. ( no idea how many times she came!)