  To study the post-main sequence evolution of the Solar system and
exoplanetary systems more accurately and efficiently, we introduce two new
features to REBOUNDx, an extended library for the N-body integrator REBOUND.
The first is a convenient parameter interpolator for coupling different physics
and integrators using numerical splitting schemes. The second implements a
constant time lag model for tides without evolving spins. We demonstrate
various uses of these features using stellar evolution data from MESA (Modules
for Experiments in Stellar Astrophysics) as an example. The results of our
tests agree with several studies in the literature on post-main sequence
orbital evolution, and our convergence and performance studies respectively
demonstrate our implementations' accuracy and efficiency. These additional
effects are publicly available as of REBOUNDx's latest release.
