  Given a quadratic CR manifold $\mathcal{M}$ embedded in a complex space, and
a holomorphic function $f$ on a tubular neighbourhood of $\mathcal{M}$, we show
that the $L^p$-norms of the restriction of $f$ to the translates of
$\mathcal{M}$ is decreasing for the ordering induced by the closed convex
envelope of the image of the Levi form of $\mathcal{M}$.
