  We propose a parametrization of the nuclear absorption mechanism relying on
the proper time spent by $c\overline{c}$ bound states travelling in nuclear
matter. Our approach could lead to the extraction of charmonium formation time.
It is based on a large amount of proton-nucleus data, from nucleon-nucleon
center-of-mass energies $\sqrt{s_{NN}}=27$ GeV to $\sqrt{s_{NN}}=5.02$ TeV,
collected in the past 30~years, and for which the main effect on charmonium
production must be its absorption by the nuclear matter it crosses.
