Is it normal to rub the edges of sheets or smooth fabrics?

I'm 55 and all of my life I find comfort when I can rub the edge of my sheet(has to be a specific cotton fabric). I'm a mom of seven grown children and hadn't done the sheet rubbing for over 20 years, but now that they are grown up, I find myself rubbing sheets edges again for comfort and to relax. I even put a cut of piece in my car so I can rub it when I'm driving along. I even do worldwide travelling now for work and I always pack a piece of sheet with me to sleep with