What Causes Watery Discharge From The Penis While Talking In The Phone?

sir i am a medical student.i am suffering from a sexual problem for last 4 year.while i talk with my girl friend through cell phone i notice there is coming a clear slipery fluid from my penis just thicker then urine even without any sexual conversation just hi hello.mostly occurs when i talk with her more then 4-5 minute.sir i am 23 years old,51 kg,unmarried,having practice of musterbation twice in a week,never experience of sexual intercourse .there is no dysuria.if would u kindly suggest me what might be the problem and what should i do,i will be very glad to you sir.