Someone might soothe themselves because they are bored, they are in a hurry because they are late, hungry or don't remember if they turned off the iron before leaving the house, if their back hurts or because they are tired need a nap and are trying to revive themselves by wagging an ankle or jumping a heal. Maybe there holding in a Fart.

So, this is not hard evidence of someone necessarily trying to deceive you.

IMO it is slightly irresponsible for this article to be used by anyone who is not truly masterful in this area as a means to interrogate anyone else. (As step parents/parents likely to do.)