Hello and welcome to healthcaremagic. I would keep a possibility of Sentinal pile/External piles. External piles can sometimes develop due to chronic constipation in otherwise health individuals. It can manifest as something protruding out during the act of defecation which can go back by itself in the early stages but if it is long standing the it may not go back by itself. There can be symptoms like pain, bleeding, heaviness etc. I would like to suggest that you see a surgeon for further advice. regards