When my son was breastfeeding, he had a habit of reaching up, grabbing my hair and twirling it around his finger as he was feeding. It became "a thing" he did, whether or not he was breastfeeding. It was really sweet. He then started to twist his own hair for comfort. Funnilly enough, my husband pointed out that it is a habit of mine too. Often in the car, we would both be staring out the window, twirling our hair.