Painful glans friction may be caused by too much force during sex or masturbation, prepuce glansitis, allergic factors, sexually transmitted diseases and other factors. 1. Excessive force: rubbing the glans too hard during sex or masturbation may lead to localized damage to the glans, which will cause painful symptoms, and may be accompanied by redness, swelling, or blood seepage and other symptoms. 2. Foreskin glansitis: men have foreskin glansitis, due to inflammatory substances stimulation, may lead to glans area congestion and edema, or even ulceration, in the friction, there will be pain, accompanied by itching, redness and swelling and other symptoms. 3. Allergic factors: for example, allergy to toiletries, resulting in localized allergy to the glans, which may lead to localized oozing, and pain when rubbing, which may be accompanied by intense itching. 4. Sexually transmitted diseases: for example, genital herpes or syphilis, which may cause the glans to erode and bleed, and after mild stimulation, there will be obvious pain, and it is contagious. If the glans is painful and accompanied by other abnormal manifestations, it is recommended to consult a doctor for appropriate examination and treatment to avoid delaying the condition.