This dream may symbolize a need for purification and cleansing in your waking life. The friend preaching loudly could represent a part of yourself that is trying to assert itself and make its voice heard. The act of using the toilet could represent a release of negative emotions or thoughts. The fact that the toilet was dirty with leftover poo could symbolize feelings of guilt or shame that you are trying to rid yourself of. Your decision to help clean the toilet could represent a desire to take control and actively work towards resolving these negative feelings. The fact that the toilet became white again could symbolize a successful cleansing and purification process. However, the black stain in the sink that you were unable to clean could represent a lingering issue or negative thought that you are struggling to let go of. Overall, this dream may be urging you to confront and address any negative emotions or thoughts that are holding you back.