To dream of a buttock or bum represents how interesting something is to you.
To dream of a beautiful and sexually attractive butt represents something you desire to have or wish to experience that's presenting itself to you in your life. A nice butt may also reflect how sexually attractive someone is to you.
Negatively, dreaming a beautiful or sexually attractive butt may be a warning against desiring something that may embarrass you. Allowing yourself to be tempted into something dangerous.
To dream of someone having an ugly butt represents a lack of interest. An undesirable situation or person.
To have an ugly or misshapen butt reflects your insecurity or belief that you are not interesting to someone else.
To see a butt fall off represents a loss of interest. You or someone else may have lost the ability to interest someone else in something you were thinking.
To dream of wiping your butt with toilet paper may reflect your attempt to respectfully rid yourself of a problem. A wish to clear yourself of responsibility to deal with a problem any further. Carefully making sure that a problem is not your problem anymore. Intelligently protecting yourself from being blamed for something.
To dream of wiping your butt with toilet paper in front of other people may reflect an embarrassment you have experienced with having to clear yourself of responsibility for a problem in front in others. Ridding yourself of unwanted relationships or problems in public view. Yelling at incompetent people in public. Feeling embarrassed at having to look unprofessional about dealing with your problems.