Is there a leptonic analog of stimulated emission (ie suppressed emission)? The phenomenon of stimulated emission is often explained by the fact that bosons are excitations in fields that are created by operators that are symmetric under exchange of order. The converse of that is the fermions that are created by anti-symmetric operators, leading to the Pauli exclusion principle. Does this phenomenon lead to suppressed emission of fermions? 
Granted, the only phenomenon that I think this would be relevant for would be radioactive decays, and those tend to be such high energy phenomena that it's hard to imagine an electron cloud in ordinary matter suppressing beta decay in any significant way (maybe in the cores of white dwarfs or neutron stars?). That or in radioactive decays where the half-lives are too long to measure reliably.
 A: Yes, this certainly occurs in neutron star interiors.
Neutrons are unstable (in a vacuum) with a half life of 10 minutes. But neutron stars are made mostly of ... neutrons. Now you could argue that this is just a consequence of equilibrium processes that ensure the Fermi energy of the neutrons is equal to the sum of the Fermi energies of the protons and electrons (and it is). However, it is also the case that the decay of neutrons and its inverse process (neutronisation) are strongly suppressed by the Pauli Exclusion Principle and the fact that all quantum states are occupied until you are within $\sim k_B T$ of the Fermi energy.
If that were not the case, consider the following: The specific heat capacity of the degenerate neutrons is very low - the normal heat capacity of an ideal gas is lowered by a factor of $\sim k_B T/E_F$, where $E_F$ is the Fermi (kinetic) energy and this ratio is at least a factor of 100 even in neutron stars with interior temperatures of $10^9$ K. If all the neutrons were to decay, allowing a (anti) neutrino of energy $\sim k_B T$ to escape each time, then the neutron star would cool down on a timescale of the neutron half-life divided by 100.
It is the blocking (or suppression) of (inverse) beta decay that slows the initial neutrino cooling of neutron stars to timescales of hundreds and thousands of years.
