The most common condition for a fleshy lump on the outside of the buttocks is hemorrhoids. External hemorrhoids are located below the dentate line and are lumps formed by varicose veins or inflammation of the skin of the anal folds, hypertrophy, connective tissue hyperplasia, or thrombus stasis. External hemorrhoid surface covered with skin, can be seen, can not be sent into the anus, not easy to bleed, with pain and foreign body sensation as the main symptom, clinical often divided into connective tissue external hemorrhoids, varicose external hemorrhoids, inflammatory external hemorrhoids and thrombosed external hemorrhoids. Internal hemorrhoid is located in the anus above the dentate line varicose veins forming a mass, the surface is covered with mucous membrane, often painless blood in the stool and hemorrhoidal prolapse as the main symptom. Among them, internal hemorrhoids of degree II or above often form mixed hemorrhoids, manifesting the symptoms of internal and external hemorrhoids at the same time. There may also be anal papilloma prolapse from the anus, anal papillae due to feces and chronic inflammation of long-term stimulation, enlargement and hardening, the disease is insidious, the disease progresses slowly, the cure is good. Another possibility is condyloma acuminatum, which is caused by human papilloma virus infection, with perianal and genital area proliferative damage as the main manifestation of sexually transmitted diseases. So you need to go to the hospital first, clear diagnosis and then treat accordingly.