What is a skin tag, why do ..

like a little knob of skin with a tiny bit connecting it to the rest of you that just appears one day out of nowhere

if they are somewhere that can't be seen, tie a piece of sewing cotton around it, it will dry up and fall off within a day or two

Skin tags are just what you describes. There is nothing wrong with them and they aren't harmful.

They don't go away, but you can get them removed.

You can do it by yourself (my brother sterlized nail clippers, and clipped his off) but they can be dangerous and they bleed a lot.

No, they won't go away. It happens a lot if ur pregnant. Go to doc and they can take them off. U can take them out urself but hard if u have a lot. They hurt if u take them urself and bleed.