i think you need to fess up to what your true feelings are and act on them, regardless of his wishes or expectations. so the first question is, how do you really feel? you didn't say how you liked your make out session. i think that if you really like him alot as a friend, and also like his kisses, there could be more than you've acknowledged thus far in your feelings for him.
so it all comes down to your feelings. if you find kissing him pleasant, i'd continue. with your basis of friendship you really don't know what this could turn into. which brings me to my second point. if you don't like his kisses, don't continue. then it really is just a friendship. if that's the case, you're not doing him any favors by 'giving him a bone,' as you put it. if you don't like touching him, don't. you'd be doing him a favor in that case by being true to yourself, because the relationship could never go anywhere, and you're wasting his time by keeping his attention focused on you.
people don't normally go to the lengths you have - kissing, possibly sleeping, with someone else unless there's something beneath there. so i think perhaps you're getting something real out of it too, and haven't admitted it.