It could also possibly be mucus from your GI tract. It can sometimes show as 'thready'.
If you've been suffering from any type of BM that has irritated your intestinal lining, your body could/would produce more mucus than normal to help protect those inner layers of cells.
Mucus is always present in our stool, but only noticeable when our GI tracts produce more to protect themselves from what they preceive as an irritant/toxin, etc.
Really hard to know what it is you're seeing..so this is just another possibility to consider.