A pirouette is a full turn on one foot, which, in tango, requires a soltada. Both partners may pirouette.
The partners may maintain contact with the hands by making a change of embrace or may drop it completely.
Whether you have contact or not, when making a pirouette, use lateral shoulder flexion to draw your elbows toward your chest so you don’t smack your partner in the face.
By Lambtron – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=31846371