Eyelash Extensions should not be mistaken for a type of false lashes that can be bought and worn by you at home. Eyelash extensions are put on with an adhesive that is kind of semi-permanent. Lash extensions are put on both your natural lashes individually. A professional eyelash stylist or a lash artist does this in the salon. Eyelash extensions are commonly applied to the upper lash line alone, and not to the bottom lashes. There can be exceptions though.