How to climax instead of urinating?

I recently got the Helix and have used it twice now with decent results. During 2 multiple hour sessions using a variety of positions and methods, I have been very close to reaching a prostate orgasm. However, both sessions whenever I got dangerously close to that sensation, I had to urinate. It wasn't just an urge to urinate, it just kind of got to the point where I couldn't hold it in. I urinated before both sessions and even after urinating during this sensation I kept getting the feeling to urinate instead of reaching an orgasm.

Before/during the urinating feeling there was a little prostate fluid and I know that I was close. Is there any particular method to "finishing" once you've reached a build up without just urinating? Contracting with every breath or holding a contraction for a big release hasn't seemed to work– is there a particular method or position that will help me reach orgasm instead of urinating?