Dear Welcome to HCM We understand your concerns I went through your details. I suggest you not to worry much. The yellow stuff you are mentioning could be a mixture of urine, semen, dust, microbes and may be some vaginal fluid. If there is no other symptoms like itching or burning, there is nothing to worry. Masturbation is not wrong. But if you masturbate few time daily and also indulge in sexual activities, my I ask, Don t you have anything else to do? In that case, you are prone to have anxiety and apprehension about sexual matters and sex organs which might lead you to a disaster. Reduce masturbation to once a day. Don t have unprotected sex. Concentrate on studies and career. Keep sex aside and enjoy it within a limit. For sexological and psychological counseling visit http://psychocure.webs.com/ Hope this answers your query. Available for further clarifications. Good luck.