ok, so if
sage were posting more, she'd tell you to both read
The Guide to Getting it On.. My guess is he doesn't know what he's doing, so he's nervous (loses erection) and and confused. you need to find a way to help him learn how to make your motor go vroom vroom vroom...it's not really all that intuitive for beginners.
so communicate...but you're probably going to need to teach him
how to do it if he doesn't a problem with oral sex. if he does...
edit: i swore too much...all this colorful language...me oh my! i just like cursing...as
roach might say: mea culpa.