Hello, You are a sportsman, you are suffering from yellow hairs under your testicles that causes foul smell on sweating. You are suffering from a bacterial infection, trichomycosis pubis that causes change in color of pubic hair. You are suggested to take care of your hygiene. Take bath regularly. Gently rub the affected area while washing to help disrupt and clean the biofilm caused due to the bacterial infection. Properly cleaning the affected area helps to increase the permeability of antiseptics (aluminum chloride). Shaving the affected area helps to prevent recurrences. Recurrences of trichomycosis pubis are prevented by keeping the groin area dry and clean. Antiperspirants with aluminium chloride reduce sweating. You can use antiseptics such as benzoyl peroxide gel or wash. It reduce bacterial colonization and hence spread. The area may be moist & warm and hence prone to fungal infection. You can use antifungal ointment, clotrimazole on the affected area from time to time. Antibacterial soap like Cetaphil cleansing soap or antibacterial bar are effective. Topical application of antibacterial ointment like clindamycin, erythromycin and Fusidic acid effectively control the infection and odor. Anti fungal agents like Clotrimazole powder or ointment are effective and curative. Take care of your hygiene, take bath if you sweat & keep the private area dry and clean. It should go away in a few weeks. You can also consult a dermatologist if the infection is resistant & takes time to go. Stay away from addictions if any. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician