  We present an effective hydrodynamic theory of electronic transport in
graphene in the interaction-dominated regime. We derive the emergent
hydrodynamic description from the microscopic Boltzmann kinetic equation taking
into account dissipation due to Coulomb interaction and find the viscosity of
Dirac fermions in graphene for arbitrary densities. The viscous terms have a
dramatic effect on transport coefficients in clean samples at high
temperatures. Within linear response, we show that viscosity manifests itself
in the nonlocal conductivity as well as dispersion of hydrodynamic plasmons.
Beyond linear response, we apply the derived nonlinear hydrodynamics to the
problem of hot spot relaxation in graphene.
