Since dreams are exploring insecurities so that you can transcend them, often you will dream of doing something that leads to embarrassment. Dreams push you out of your comfort zone so that you can be who you are - independent of what others think of you. In new situations when you are revealing yourself to others, you may dream of being underdressed, in your underwear or going to the bathroom in front of others. Feeling like your dress isn't appropriate is the same as feeling that who you are doesn't quite 'fit in.' Evert aspect of nature is unique and human beings are no different. Even among family members - you are a unique variation of your the line you carry forward. The dream is showing you that you are indeed, different and should cherish what makes you unique.
Being in your underwear or revealing yourself intimately is the same as overcoming the need to hide. Its okay to share your feelings with others. That is what real friendships are based on. If you have done something in a dream that makes you feel embarrassed - you may be awakening to the way the Trickster mechanism teaches you to lighten up, stop being so serious so you can laugh at yourself. See also Naked.