Charles is right, while the responses have been funny, it is a good question to ask and one that many folks may have some wisdom to share.
You might want to consider taking a course or workshop in Tantra, or if that is too over the edge, at least try Yoga.
Usually for men, losing control over their orgasm can be easily corrected with some training in bio-feedback techniques and breathing exercises. While getting a blow job, or having sex next time, try taking very deep, slow breaths. When you inhale focus on your control, when you exhale, let out your pleasure as you blow out and whisper the letter "A."
You should also practice Kegel squeezes during the day, perhaps when sitting at your desk or driving. It is sort of like doing crunches for you cock. I don't want to bore or gross anyone out here, but what you are doing is practicing your ability to shut off your orgasm, if it feels like it is racing away from you. There are a number of providers out there that know how to use the squeeze technique. Seek them out and have them show you and practice your Kegels while she applies her thumb and forefinger to the right pressure points.
After a few sessions, you will be amazed at the control you will muster.
Have fun!