  We investigate how damping the lowest Fourier mode modifies the dynamics of
the cubic Szeg{\"o} equation. We show that there is a nonempty open subset of
initial data generating trajec-tories with high Sobolev norms tending to
infinity. In addition, we give a complete picture of this phenomenon on a
reduced phase space of dimension 6. An appendix is devoted to numerical
simulations supporting the generalisation of this picture to more general
initial data.
