Your first time is just going to be about
finding what's best for you. Honestly,
it's not really about "pleasing" each
other...but more about just finding what
works.
I would suggest you being on top. You can
control the movement, how deep he goes,
etc.
Just relax...and go with the flow. I know
it doesn't sound like advice, but it's the
BEST advice for the first time.