Hello dear, Thank you for your contact to health care magic. I read and understand your concern. I am Dr Arun Tank answering your concern. There are many causes of such a white discharge. You have to rule it out first to exclude the possible causes. When urine dries it leaves some salty thing on the undergarments you have to exclude it. Semen discharge some times cause white layer on the undergarments. If you have burning in the penis while urinating it is urethritis. Urethritis is the only cause which requires a treatment. Associated burning in the urine, discharge, pain in the surrounding area are the main feature of this urethritis. It is associated with sexual exposure. Suitable antibiotic therapy, avoidance of intercourse, using condom, trewtmrnt of both tbe partnet is all necessary steps require to cure this STDs. Drinking plenty of water and maintaining local hygiene is also help curing the infection. I will be happy to answer your further concern on bit.ly/DrArun. Thank you, Dr Arun Tank Infectious diseases specialist, HCM.