D defensive move where a fighter leaves her front arm low and drapes it across her midsection so that when her opponent throws a punch she can use her shoulder to block or roll with it. This is so the defensive fighter is able to counter back with either hand because neither was used for blocking.
For a right-handed fighter, it also automatically shifts her weight to her back foot and sets her up for a hard counter right cross.
Most known Floyd Mayweather has become known for this, many great fighters like Jersey Joe Walcott were masters of this defensive technique.