Figure 3a shows the evolution of the orbit orientation on an orbital period P timescale. Three precessions are experienced: an in-plane precession (left panel) with contributions at 1PN, 1.5PN, and 2PN; and two out-of-plane precessions, namely, one around the minor axis (middle panel) and another around the major axis (right panel) with contributions at 1.5PN and 2PN. Figure 3b shows the evolution of the orbit orientation on a secular timescale P^cone ≫ P (see Eq. (E.1)). The orbital angular momentum experiences a precession around the black hole spin axis.