What does ejaculation/orgasm mean in a dream?

It's difficult to say what it means because for one, it depends on how you feel about him, and secondly, it wasn't you that achieved orgasm. I think, if you like him, it's probably just a reflection of how you feel, and you said you're both shy, and in this dream, you seemed quite forward. That might just be the other side of your personality coming through in the dream world, where you can't properly express yourself in reality. Not achieving orgasm in a dream signifies some sort of frustration. Adding the fact you were quite aggressive with him, it's probably that you're angry at the situation and want something more, or want to patch things up with him. Hope that helps! :)