  We consider the ISM of flocking and swarming. The model has been introduced
to explain certain dynamic features of swarming (second sound, a lower than
expected dynamic critical exponent) while preserving the mechanism for onset of
order provided by the Vicsek model. The ISM has only been formulated with an
imitation (''ferromagnetic'') interaction between velocities. Here we show how
to add position-dependent forces in the model, which allows to consider effects
such as cohesion, excluded volume, confinement and perturbation with external
position-dependent field. We study numerically a one-particle case.
