It's the motion at the 3 second to 4 second mark here where the capoeiristra pivots so that their side faces their opponent and they're sitting back a bit. It's often done before a Queixada, particularly since it works well for a partner drill where capoeiristras trade kicks, using this defense to avoid the incoming kick while setting up for the next, but I've also seen it suggested as a defense against a Bênção or Chapa (moving back from the attack while potentially moving to the side of it) or against a more lateral attack by turning your back to it, either catching the kick along the flat of the back to reduce its force (and because the back is not a valid target in the roda, thus negating the hit) or to facilitate ducking under it.
The description in the above-linked article is:
From the base position of the ginga, with one leg pointed backward, shift the chest in an orthogonal line to the opponent, turning on the two feet; bend the legs at the knee, sitting on the pelvis (a straight leg can be an easy target, and it hurts bad).
When stepping into the movement, I've often seen it described as Entrada. When I was studying in Philadelphia, Mestre Doutor had a name for it, which I think might have rhymed with "Queixada" because I remember him prompting the moves and I remember the two going together, which could match with it being Entrada other than that sounds backwards since you're retreating, not entering.
Ah, and I have found one pictorial reference. It's the first two steps, here depicted as the setup for a Queixada courtesy of this site:
