Wiping Away Sweat
Preparation:
Drink plenty of fluids before the session. Learn to sweat profusely. Carry a small towel inside your keikogi.
Application:
Sweat. Then step back, produce your towel, and mop your brow, neck, forearms, nose, chin, brow again, and anything you can get away with.
Pros:
Although you can't steal much time with a single application, if you develop this technique properly it can become an unquestioned, possibly completely overlooked, habit which cumulatively results in hours of time wasting.
Cons:
Often you have to work hard to sweat.