Don't wear clothes or undergarments that are too tight. Very tight clothing can impede the flow of air around your body and produce excess perspiration, especially in the backside region. Select garments that are well fitted and stay away from too many synthetic fabrics.
Wear natural fibers, such as cotton, linen and silk. These fabrics breathe and allow air to circulate around the body. Many underwear manufacturers produce cotton and silk underwear that is attractive and breathable.
Dry off well after your bath or shower, and then sprinkle some cornstarch-based body powder on your butt. Cornstarch helps absorb excess moisture and can keep your sensitive areas nice and dry. You can even take a small travel sample with you, so you can reapply it during the day.
See your doctor for medical advice if you find yourself perspiring uncontrollably. There are medicines and other remedies available for those who sweat profusely.
Freshen up several times during the day. Sometimes, the only thing you can do is take a quick pit stop and dry off your butt. This is one of the most effective remedies.
Lighten up and don't be too concerned about a mild case of sweaty butt. Sweating is a natural and beneficial--though sometimes bothersome--function of the human body. Let your body work in the way it was meant to as long as you don't suffer any ill effects.
Look for specialty garments designed for exercising. These clothes wick moisture away from the body and dry quickly, allowing the body to remain mostly dry.