Let
be a diagram in $\mathsf{Cats}_{\mathsf{2}}$.
-
The left whiskering of $\alpha $ with $G$ is the natural transformation[1]
\[ \text{id}_{G}\star \alpha \colon G\circ \phi \Longrightarrow G\circ \psi . \]
-
The right whiskering of $\alpha $ with $F$ is the natural transformation[2]
\[ \alpha \star \text{id}_{F}\colon \phi \circ F\Longrightarrow \psi \circ F. \]
