The man, known only as TBoneTheOriginal, posted his story - on the site Reddit.
Readers were so intrigued by his post - entitled 'I have no butt crack' - that he has been answering questions ever since, including that all important question, that he 'poops just like anyone else'.
TBone explained that he'd needed the surgery to sew his buttocks together after being diagnosed with severe pilonidal cysts.
These are painful boils that occur at the end of the tailbone or between the buttocks.
It is unclear why they occur, but it's generally thought they are caused by loose hairs that push into the skin.
Certain things can increase the chances of developing a pilonidal cyst, such as being obese, having a large amount of body hair and having a job that involves a lot of sitting or driving.
TBone added: 'I've had multiple surgeries on it [the cyst] and instead of the usual procedure which involves letting it heal, mine was so bad that a plastic surgeon had to close it up. But they keep coming back, and it'll probably just get worse as I age'.
After several operations, his surgeon decided to close the space eight years ago to try and prevent the problem from recurring.
TBone added: 'I've had multiple surgeries on it [the cyst] and instead of the usual procedure which involves letting it heal, mine was so bad that a plastic surgeon had to close it up. But they keep coming back, and it'll probably just get worse as I age'.
After several operations, his surgeon decided to close the space eight years ago to try and prevent the problem from recurring.
