my advice is to lay back and enjoy
ahhhhhhhhhhh
we had a regular for awhile, for mfm, and he was very large.
i was nervous and all, but he took it slow and it worked out well.
actually, i was sore for a few days after that. felt like some muscles had been worked out.
but like one of the other posters said, you can stretch it out some.
it took a few times, .. and it may take you a few times as well, to "loosen" up, but you will.
and once you do ...
thats when you can lay back and enjoy.
but be sure to stay on top until you get acclimated
ive always said size didnt matter, but a really big one is nice. being "filled up" is great
jana