Eliza, my dear, what fun you have waiting for you. There's lots on the web under (surprise, surprise!) "anal". A good one is http://www.puckerup.com/anal_advisor/anal.htm by Tristan, a clued-up lady whose profession seems to be anal sex. (Can you imagine explaining a job like that to the IRS?)

Another thing you might like to start with is to lube up between your cheeks and amuse your man by sliding him up and down between them. This feels good for you - as he brushes back and forth across your star - and also feels very good to him, especially when you squeeze with your muscles. This works well lying on your sides with your legs straight, but you can also do it on top riding him cow girl. On top gives you complete control and you can experiment with pressing him against your ring and 'kissing' the head of his cock by pushing out with your muscles. The idea is to have fun and just dip your toe in the water. You will greatly enjoy having him come pressed against the spot.

As you get more adventurous, follow Tristan's advice. And use lots and lots of lube. Do let us all know how you get on - we deserve a small share of the fun.