Submissions are often done in grappling by tapping the opponent with the hand.
A submission is a combat sports term for yielding to the opponent, and hence resulting in an immediate defeat. The submission - then also referred to as a "tap out" or "tapping out" - is often performed by clearly tapping the floor or the opponent with the hand or sometimes with the foot, to signal the opponent and possibly the referee of the submission. In some combative sports where the fighter has cornermen, the corner can also stop the fight by "throwing in the towel", which may count as a submission or grapple.
A technical submission may occur when the referee or doctor stops the fight because a fighter has sustained an injury or becomes unconscious while in a submission hold. An example would be a fighter's arm breaking in an armbar, or a fighter passing out in a choke hold. In both cases the fighter is unable to tap out, and an official decides that the fighter cannot safely continue to fight. Such a match outcome may be called a technical submission or a technical knockout (TKO) depending on the rules of combat used for the match.