In ballet, when two dancers dance together it’s called a pas de deux. The pas de deux is one of the most compelling vehicles in classical ballet and is used to express emotions such as love, jealousy, or anger between two dancers. In addition, partnering offers the opportunity for one dancer to support the other while executing a step or sequence of movements that the other dancer could not perform alone.
Partnering requires strength from both dancers. A man may lift a woman high into the air, but the ballerina must keep her torso strong, otherwise the lift will not be successful. When partnered, a ballerina can do many more supported turns than she could by herself and can lift her leg higher and sustain her balance much longer.
Classical partnering and lifts are learned in pas de deux class, which is part of a ballet’s student’s training curriculum. In a pas de deux class you might learn the exciting and difficult pirouette-fish dive sequence performed by the pricipal couple in Aurora’s Wedding in Act III of Sleeping Beauty. The enchaînement or sequence of steps begins with the woman taking the man’s arm and pushing off into several turns or pirouettes as he supports her. She then actively pitches her body forward in a dramatic fish dive to be caught by her partner just in time. The man lifts her upright and they start the enchaînement again.
A Grand Pas de Deux is often the culmination of a typical classical ballet, and the dance for a man and a woman follows a traditional sequence: the couple dances together, then the man dances a solo variation, followed by the woman’s solo variation. The Grand Pas de Deux finishes with a fast-paced coda or final dance.
In contemporary ballets the partnering is just as challenging for each dancer and doesn't follow any prescribed rules. You might see men supporting women, women supporting men, men supporting men, and women supporting women.