Here at UX Coach we sketch all the time.
We sketch everything possible.
For our course brochures we sketched the template for each session.
This happens before we design the high fidelity outline.
So we follow the User Centered Design approach to everything.
Sketching helps us aid the conversations we have.
With it we ensure that everyone is seeing the same picture and shares the same vision.
It also speeds up the process of decision making and agreeing on next steps.
All sorts of surfaces are canvases for sketching.
A napkin is often one of the most accessible of all.
We do not stray away from sketching on a back of a napkin quite often.
Make sure you capture the sketch in digital format to share it with the team or world at large later.