It sounds to me like you need to have a good sit down and get things spread out on the table. How I would go about it is to go do something that neither of you would think of as "date" material so there isn't any pressure, but there also are not a whole lot of people around to make talking about things awkward.
Tell him why you are frustrated. Perhaps that he led you on and whatnot. Tell him how you feel now (as you told us you just want to be friends.) It is possible he feels that because he told you those things that you expect more from him than a friendship. Clearing the air of miscommunications can work wonders.
In the meantime, I would stay clear of all dares and whatnot that lead to you hooking up with him. This can send him mixed signals as well, and let's be honest, girls like to hook up, guys like to hook up, but if it's not talked about it can lead to really awkward things. I would also suggest being COMPLETELY honest with him by telling him that it was a dare (if he didn't know already) and saying that you want him back as a friend.
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"If you stand in front of a mirror holiding a dozen roses, you'll see
thirteen of the most beautiful things."
"Don't have regrets because at one point, you were doing exactly what you
wanted to."