  Observations of Type II supernovae imply that a large fraction of its
progenitors experience enhanced mass loss years to decades before core
collapse, creating a dense circumstellar medium (CSM). Assuming that the CSM is
produced by a single mass eruption event, we analytically model the density
profile of the resulting CSM. We find that a double power-law profile gives a
good fit to the CSM profile obtained using radiation hydrodynamical
simulations. With our profile the CSM is well described by just two parameters,
the transition radius $r_*$ and density at $r=r_*$ (alternatively $r_*$ and the
total CSM mass). We encourage future studies to include this profile, if
possible, when modelling emission from interaction-powered transients.
