When a layer of functional call indirection no longer serves a communication or factoring purpose, remove it by textually substituting the body of the function at the call sites. The inverse of ExtractMethod, and by far the less common of the two.
Analogously: DenormalizationIsOk
Given that most languages will do this as an optimization, or can be told to do this (the inline keyword in C/C++), this should be very rare. I would only recommend InlineMethod in two cases:
Also an optimisation performed by some compilers, whereby a method call is replaced by the actual code of the method being called. More usually referred to as MethodInlining.