My advice would be it's not a race. Slow down, so much more to a blowjob than up and down. Take your mouth off, go up and kiss him a bit...suck/gently bite his nipples and go back to his cock. Enjoy it. Rub it on your face...lick the frenulum, put it back in your mouth...leave it there and do not go up and down. Suck gently, then go up toward the head of his cock...lick around while still in your mouth....take your mouth off and go down to his balls.....always easy and never hard suck them, go back to his cock...tell him to kick back and relax and enjoy the waves....take him slowly in your mouth...there's no appts to get to, take your time...if you get the signs he is getting close, take your mouth off, wet a finger or two and GENTLY insert into his hole, go back to his cock and as you rub his prostate, SLOWLY, do the same with his dick, eventually take his dick down the back of your throat and simply "throat suck" as long as you can. I got a feeling you will be rewarded with several ropes of cum shooting down your throat...do not suck harder at this venture...slowly work up and if his dick is relaxing suck it nice and easy, yeah, like that. Good boy.