In practice it is enough to simply angle the thermometer towards the direction of the ear canal. More specifically you are trying to target the direction of the tympanic membrane located in the middle ear (one of the parts of the ear; the other parts being outer and inner)
Some maneuvers, although not completely necessary, may include pulling the ear lobe upwards and outwards for babies. This is to straighten the ear canal and is more often done when using otoscopes. For adults, we pull the ear downward and outward.