What Causes Bad Odour To The Body?

hey i am a freshman in highschool. and this problem hasnt came up ever in my life. it all started a week in a half ago. when i entered my new classes. i started to notice the problem when people who sat next to me in classes would make sniffing noises or faces of discomfort. im very hygenic i guess. to be honest just last week i cleaned my butt inside with soap.... i mean i was my body and hair. but i dont know.. anyways. this whole week i had been cleaning my rectum twice a day and using deoderant powder (talcum). but when i came to school today people could still smell it. and its been getting worse since it started that only the person next to me could smell it now almost the whole back row can. please help..