The dab is a dance-like arm movement that is intended to act as a "yeah!" or exclamation point at the end of
something. It might come after a dope dance sequence (and thus actually be a dance movement), or it might come after achieving great success in some other activity.
It involves lifting both arms up in front of your body to slightly above parallel, and then dropping one arm to the side of your body - at about parallel to the ground - while simultaneously smelling the
elbow crease of your other arm.