I can’t finish ☹️

Okay so me and this guy I sleep with have tried so hard to get me to finish but ya girl CANT like I don’t understand what I’m doing wrong. He’s doing the best he can and I feel like I’ve been close a few times but the feeling never came to a release, it was just super intense for a few moments and then I had to stop because it was too much for me to handle... ANY ADVICE??? we are both frustrated because it shouldn’t be such a challenge to get me to cum.