This is actually not that deep as far as dream interpretation goes, but the fact is, some bodily processes can’t shut down all night especially if you have been suppressing them for a long time and a bowel movement is a perfect example of that. Sometimes you just need to let it out and no matter what time it is, even if you are asleep, your body will draw up images of it in order to wake you up. Have you ever had to urinate in the middle of the night and consequently dreamed of toilets or waterfalls? This is the same basic principle.
Have you had a dream in which you were making a bowel movement and everyone you knew was watching you, or that you were pooping in a toilet and someone kicked in the door and saw you doing it? This suggests even more embarrassment with the corporeal form. Some humans are basically sad about their bodies and their makeup. We feel as though we are inferior for all of the bodily functions that we must participate in when in reality they are simply necessary and everyone does them.
That said, having a dream in which others watch you make a bowel movement can also be representative of general feelings of embarrassment. Have you done anything silly lately that you felt like people should make fun of you for? Have you made any stupid mistakes or have you accidentally bared your naked body to someone? Any of these things might represent a reason that you would be dreaming of having a bowel movement.
Sometimes the toilet can represent a place of purity and cleansing. To dream that you have a bowel movement in a toilet can simply be suggestive of the idea that you are finally clean and that you have been trying to get something off your chest for a while. Do you have a secret to tell or something to say that you know you will be suppressed or not taken well? Do you feel dirty and like you need to clean yourself. Perhaps you feel burdened with stresses and need to alleviate yourself from some of that. All of these might be reasons that you dream of having a bowel movement in the toilet.
Think about that the next time you have a bowel movement in your dreams. It is nothing to be embarrassed over. In fact it just means that you are doing some necessary maintenance on your mind and soul. While in real life this is regular body maintenance, in the dream world this represents alleviation of the mind, something which is of equal importance in life and should be noted as such. Don’t be so embarrassed about your body in the future.