Inside out lining. The lining of lower rectum can become lax overtime and be forced out during a bm. If it goes back in, it is what's called a grade ii prolapse. If it needs to be pushed back in, it is grade iii. If you are having prolapse with each bm, you need to see a surgeon before it gets worse.
Prolapsed hemorhoids. Prolapsed hemorroids are the hemorroids which are sticking out of the anus and are very painful most of the time and some times they are thrombosed, which means there is ckott in these prolapsed veins. These can be felt with your finger and are very painful to touch and sit as it rubs against the buttocks. It needs to be treated with sitz bath and local suppositories and cream to reduce swelling, pain.