when I sit with a girl , and sexual feelings arrises in my mind then viscous watery liquid type material comes out from tip of my penis ,due to this my undergarments or whatever after it gets wet. sir this problem arrises only when sexual feelings comes in mind.otherwise I don't face it in normal situation .So ,I ask you that is it a problem or a normal case of young boy of 19 years old.l am totally confused so plz suggest me sir...