Answer:
My first is in some but not in all. My second is into but not in tall. My third in little but no in big. My fourth in port but not in pig. My whole is made in nature's way. For clothing, rugs used every day.
This is in a realm of true and in a realm false, but you experience me as you turn and toss.
Take off my skin, I won't cry, but you will.
I'm not really more than holes tied to more holes. I'm strong as good steel, though not as stiff as a pole.
What is pronounced like one letter, written with three letters. And belongs to all animals?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?