My poop come out in like a string sometimes what is that?

If only occasionally: If poop comes out like a string only occasionally, that is less worrisome, and may just be the consistency (hardness; water content) of the poop and the amount of relaxation of the anus (tight anus causes smaller diameter poop, if soft poop), at the moment of the bowel movement. But, if string-like poop happens often, one has to make sure there is not a cancer or blockage in the anus or rectum.