By underwear do you mean a pullup? Do you suppose the pad is the problem? During the day at school or work Ill wear either a light pad or a pullup, I have though worn a pad INSIDE of a pullup, thinking itd be easier to just toss the pad and have the underwear as backup where carrying extra pads and panties wasnt convienent. Whenever Ive done this ive noticed the leg cuffs are sometimes damp if the pad is very wet