How to feel more relaxed when trying to climax?

So I recently started using a vibrator and I'm trying to be more comfortable with the sexual experience and all.

I noticed that I get really tense and pull away everytime I feel like I'm hitting the right spots for orgasm. The feeling is so intense for me that I can't seem to handle it.

Any idea on what to do? I try to control my breathing and focus on the pleasure.