1:

Before using your mug for the first time, inspect it carefully for signs of ceramic hysteria. Do this in a darkened room so as to not alarm the face mug. A startled face mug may bolt through a cupboard, taking out everything in its path.

2:

Do not look directly into the face of the mug. Rectilinear viewing of a face mug may cause lightheadedness, paranoid delusions, and unbridled male enhancement. The growth of additional heads has not been unreported.

3:

Place the mug on a flat, level, earthquake-free, non-skid mobius surface, away from pets and small children who may become disturbed by the mug's presence.

4:

With feet firmly planted in six inches of topsoil, visualize pouring a liquid into the mug. Keeping the open end of the mug up, now fill the mug with your hot or cold beverage.

5:

Do not use mugs in direct moonlight and always wear protective eyegear. Enjoy your mug!

Do not drink hot liquids while standing on your head.
Do not attempt to drink coffee through your nose.
Do not hit yourself or other sentient beings with a face mug.