Aspiration means breathing - so the addition of an Aspirated effector means the sound is made breathing in or out - i.e. using the lungs. No Aspirated effector present means the sound is made using air in the mouth or with the airway (epiglottis) closed. Such sounds are called injectives or ejectives.
The following diagram shows where the Aspiration is made in the mouth.
The Aspiration is used in the following sounds: