Two things crossed my mind that are sort of similar to what you're describing, fetishes & security blankets. They aren't ocd but the compulsion is there. Fetishes are reportedly sexually motivated, & of course security blankets (& sometimes teddy bears, etc.) are self explanatory. So there must be a number of causes & motivations for these kinds of behaviors. There are probably specialists who study behaviors of this sort. Maybe try to google various compulsive behaviors?