Underwear Sizing Guides This sizing guide was designed to help you find the best possible fit of your XEBEX product. For proper waist measuring, use a pliable tape measure. Find your natural waistline and measure at that spot. Our modal premium boxer briefs are more flexible than cotton and allow for more variance between sizes. The longer cut no-rise legs offer a snug fit without chafing. Our cotton trunks are a shorter cut which allow for more air-flow. Cotton flexes less than modal and is a slightly thicker fabric. Problems with Chafing?Here are some easy ways to prevent it:Dry off your skin regularly. If you know that you sweat profusely on certain days, try to keep that area dry. If your tight clothes are causing you to sweat more, wear looser clothes to help your body to stay cool.Keep your body temperature lower. Drink plenty of water and stay hydrated and cool.Powder your inner thighs. This can soak up the moisture and sweat and calm your skin. You can purchase specialty powder for this at drugstores or online. Wear anti-chafe underwear, like our premium modal boxer brief. The right kind of underwear will keep your thighs and skin comfortable.