well there is a post somewhere here with the rules for girls about guys
it goes something like this
subtle hints DONT work
obvious hints DONT work
direct hints DONT work
you need to TELL him

+ he might be afraid that he will go too far and hurt you. Remember the programming us guys get from our mothers?
Talk and let it take some time. Perhaps you should print the hottest story of the forum and slip it into his attache bag or something or "hide it" poorly so that he will find it and then he might know what you want, without you actually having to tell him (if that is a problem).

take the "hard limit" test and give it to him and ask him to fill out his part then you sit down and compare over the kitchen table after 2 glasses of wine perhaps?

some thoughts that might help.
good luck to you and your newbie Dom.

edit: omg smilie at the lack of punctuation