Caressing pillowcase

I have caressed my pillowcase since I was a baby. It has to be a stiff pillowcase, and I kind of fold the opening into a point and then rub my fingers, or inside and outside of my hands. Sometimes I like to count each stroke. Or sometimes I will stroke a certain amount of times per finger. Like, one time for index, 2 times for middle finger, 3 times for ring finger, etc. I also will do it on paper edges, or crisp button up shirts at the edge where it buttons. It just feels nice and it's soothing. It's nothing sexual at all. It is relaxing. I know others do variations of this. I never do it so much that I callus my fingers. I do it softly, but any chance I can. Sometimes if I don't have something available to rub, I long to do it. I really just want to know why I have this habit, and why since I was a baby. It's it ocd?