To wash underwear means that to you is what to be ashamed and what to hide from people around. Dirty underwear warns that around you various gossips for which you gave a reason go. If in a dream you see a beautiful women's underwear, then in real life it is possible to call you the judge fine. You are an expert in art and have congenital taste.
Be sure and keep any other thoughts out of your mind before drifting to sleep as a cluttered mind can decrease the chances that you will remember your dreams upon waking. Also, focusing on remembering your dreams upon waking in the morning is another very important thing. This sounds very easy, but is often hard for some to do. Interpret a dream by "dictionary dream of interpretation"
When you very first wake up, simply think about your dreams. Don't allow your mind to drift off to other things, just lay there and think about the things you dreamt about the night before - dictionary dream meaning.