This will help wash away any dirt, debris, oil, and sebum that is causing you to break out below the belt line. Use a gentle soap or body wash. You can even look for one that's formulated to take care of bodily acne. Use a gentle, non-comedogenic exfoliating cream and a loofah. The exfoliation will remove dead skin cells that may be clogging your pores. Use a soap with at least 2% benzoyl peroxide. This will help clean out excess oil and help to clear your pimples. Treated toilet paper can cause chafing and promote the growth of pimples. There are specific detergents for people with sensitive skin as well. Use these products whenever possible to avoid irritation or an allergic reaction that might be caused by your current detergent. The more breathable your clothing is, the less likely you are to trap sweat in unwanted places. Choose breathable underwear made from natural fibers like cotton.  Sweat can get trapped on your buttocks, making it a perfect breeding ground for the oil and bacteria that cause butt acne. Change your underwear frequently, and shower after sweating. At bare minimum, take one multivitamin and one Chelated Zinc tablet daily.  Vitamin A, B5, C, E, Selenium, and Omega 3 are all known to promote healthy skin.  Consult your doctor about the appropriate vitamins for you. Water does remarkable things for your skin. Be sure to drink at least 8 glasses of water per day to hydrate your body, inside and out. Certain sugary, fatty, and fried junk foods can cause an increase of insulin in the body, therefore forcing the body to produce more sebum, the cause of acne. Try to eat a low glycemic diet to combat this. At minimum, make sure you are eating a balanced diet that is rich in fresh fruits, vegetables, and whole grain foods. Sitting can prevent the skin from breathing adequately and sitting for long periods contributes to pores clogged by sweat and bacteria While sitting at your desk or computer for long periods of time, stand up for a while and/or take a short brisk walk. Even doing butt or leg exercises at your desk helps the blood circulate. It is common for those who have acne on the buttocks to retain the condition well into their late 20's, but a dermatologist may be able to provide you with a prescription that can clear up your acne. Some food allergies or sensitivities may contribute to acne patterns on the buttocks. Talk to your doctor about getting a food allergy and sensitivity test done to see if this is contributing to your bodily acne.

Summary:
Wash your buttocks every morning and night. Exfoliate the skin on your buttocks once a week. Use a toilet paper free of fragrances or dyes. Use a non-allergenic laundry soap and bleach to wash your clothes and sheets. Wear loose-fitting clothes. Try taking vitamins. Drink plenty of water. Alter your diet. Sit less, stand more often. Always see a dermatologist if the acne persists for too long. Have a food allergy test done.