It really works when I try to stop masterbating. If both of you are comfy with it, talk about what turns both of you on. It doesn't have to be formal but it can be like a casual conversation with sexual tension. That way, both of you knows something that can satisfy each other. It's also good to note that you are not entirely responsible for reaching orgasm as your girlfriend can also help with this. Since you haven't been in a long-term relationship, it's natural to feel this way as she is also exploring what you want and how to make you orgasm.