  The particles of a dark matter due to gravitational interaction deviate from
straight trajectories in the vicinity of a massive body. This causes their
density to become inhomogeneous. The developed density contrast causes a
gravitation attraction force acting upon the body proportional to its mass
squared. Since this effect depends on the body's velocity, it causes a specific
reference frame to stand out. The force is similar to an anisotropic drag,
which can be negative in some directions. The mean drag force, averaged over
all direction, is nonpositive. We can expect some observational manifestation
of the considered effect for supermassive black holes in galaxies.
