If 6 inches is considered small these days then I am shit out of luck with women lol.... But seriously, you shouldn't have a problem at all with girl on top positions.
Have you read the index yet? There is some great sex advice in there. As for actual positions,
http://www.sexinfo101.com/sexualpositions.shtml
It is on the homepage for this site! They have lots of different positions with a demonstration. I suggest you look for the ones you like and try them
I think you should just talk to him and suggest trying different positions until you both find the ones you like better. Communication works.. And girl on top positions are not always the best feeling for guys, but it is on most girls favorite list so he maybe you can explain to him how much you love it too.
Good luck.