Hello.
First, let’s deal with the facts and then the myths. The clear fluid you’re referring to is actually produced by the Cowper’s Gland—some refer to it as “pre-ejaculate.” This fluid is secreted prior to orgasm in order to clean out the urethra of any uric acid remaining from prior urination. It’s important for risk reduction and birth control to note that this fluid can contain millions of sperm left over from the previous ejaculation. Now to the myths: it has no magical qualities—and neither does semen. It’s not rich in any particular beneficial hormones, doesn’t firm breasts, clear up acne, make you gain weight, etc. None of these myths is substantiated by any data.
What your girlfriend is doing is massaging your prostate. According to Erika Thost, M.D., author of “Sexy Prostate: Male G-Spot Massage for Pleasure and Health,” many men and couples enjoy prostate massage for pleasure, but also for helping improve their prostate health when they’re having symptoms. I am not aware of any long-term studies regarding whether prostate massage helps to prevent cancer or other conditions. And I’m also unaware of any studies that will change production of either Cowper’s Gland fluid or semen.
For more information regarding prostate massage, see Dr. Thost’s website:
http://www.sexyprostate.com/http://www.sexyprostate.com/
And for more information about sexual response, male sexuality, etc., see Dr. Bernie Zilbergeld's excellent resource book, "The New Male Sexuality," widely available both used and in paperback. Dr. J