Inclusive muon $v_2^{\rm \mu}$ as a function of $\pT$ at forward (left) and backward (right) rapidity in high-multiplicity p--Pb collisions at $\sNN =$ 8.16 TeV, extracted with two-particle cumulants (top) and two-particle correlations (bottom). The results are obtained with three different estimators of the event activity: V0M, CL1 and ZN.