Remember the function of the anus in the body; it is to hold back waste material until it is ready to be expelled with a little pushing. Thus it represents things being held back. But because the anus is also associated with subtle feelings of shame and self esteem issues, this usually indicates that you have been holding back your true feelings of your own self worth when you are in social situations with others.
Remember that a lack of self confidence in some regards is normal and is human nature. Honestly, there are some things that certain people are good at, and some things that they are not, and when you are in the presence of someone that is better than you in some category, it is only natural to feel inferior. Now should this feeling affect the overall way that you feel about yourself in the long run, or should it affect your opinion of yourself when you are away from this person? Not at all. It may be hard to help it, but you need to know that there are also qualities you possess that nobody else does. There are things that you are good at that nobody else can do, and in the right circumstances, when people are near you, they are probably just as afraid of you as you are of them. This is also natural.
What you cannot do is let these feelings of inferiority seep into your true feelings of yourself at all times. This is wrong and represents a skewed version of reality. Not only that, but you should never determine how you treat yourself or how you feel about yourself based on the way that you are treated by others. When you see the anus in your dream, it means that these feelings of inferiority have become too hard to bear. Something is going to happen soon if you do not let them out. Try seeking professional help, or talk to a friend that you trust and that you know will be willing to listen to what you have to say. Sometimes a close friend can be the best therapist.
Sometimes the anus, having the ability to give way, or to clam up, stands for your quality in regards to how liberal you are with giving away possessions, or how stingy you are about keeping them to yourself. There are situations in which you will want to keep your hard earned goods, but when someone else is really in need of help, especially if this help is labor and does not require anything to be bought or sold, then this would be a good time for you to take some time outside of yourself and go out and help them with whatever they need. This way you will feel good about yourself after having completed the task, and you will have demonstrated your worth as a compassionate and giving human being.