It's perfectly normal to find a small amount of clear of milky discharge in your underwear. Discharge is actually your vagina cleaning itself to protect you from infection- it's very clever! The amount of discharge changes during your menstrual cycle. You only need to worry about discharge if it changes colour (to yellow or green) and if you start to feel any itchyness, this may be a sign of an infection and you should go and see your doctor. If the bothers you on your undies or they feel wet, try Nude Liners which are made exactly for this reason.