  M-dwarf flares observed by the \textit{Transiting Exoplanet Survey Satellite}
(\textit{TESS}) sometimes exhibit a "peak-bump" light-curve morphology,
characterized by a secondary, gradual peak well after the main, impulsive peak.
A similar "late phase" is frequently detected in solar flares observed in the
extreme-ultraviolet from longer hot coronal loops distinct from the impulsive
flare structures. White-light emission has also been observed in off-limb solar
flare loops. Here, we perform a suite of one-dimensional hydrodynamic loop
simulations for M-dwarf flares inspired by these solar examples. Our results
suggest that coronal plasma condensation following impulsive flare heating can
yield high electron number density in the loop, allowing it to contribute
significantly to the optical light curves via free-bound and free-free emission
mechanisms. Our simulation results qualitatively agree with \textit{TESS}
observations: the longer evolutionary time scale of coronal loops produces a
distinct, secondary emission peak; its intensity increases with the injected
flare energy. We argue that coronal plasma condensation is a possible mechanism
for the \textit{TESS} late-phase flares.
