To learn the definition of the term "headdesk" you could look it up in the urban dictionary.
Or you could just look at these cakes.

(Bonus: Read that line out loud, and every preschooler within earshot will love you.)


Which, incidentally, is supposed to look like this:

[repeated thudding sound]
[rubbing forehead] Thanks to Shawna K., Mary D., Caitlin I., Stacey S., & Angi A. for this awful headache.