the act of playing piano. although not a formal term such as practice or perform, the term pianoing is specific to having a damn good time playing the piano, regardless of it's practice or performance.

The best instrument in the world. Best played with Chopin or Grieg. Most fun to play with candles burning while it's storming outside.

playing piano in a non-toss-giving way, e.g no scales or similar crapola, just ninjaing the ivories in the lecture theatre at lunch
method for attracting crumpet that attractive but non-musical dudes can't do

Better than a guitar

The best musical instrument ever! Used to make beautiful music... and waste hours of the day on.

When your voice goes all glitchy and weird when talking on a voice chat.

Undoubtedly the best instrument ever created by mankind. The piano is not only able to play soft and loud, but it can also play multiple parts simultaneously, making a single pianist the equivalent to an entire orchestra. The piano marks the pinnacle of human music technology, which is ironic (but should not be surprising) because it was invented in the 18th century.

Should not be confused with a keyboard, a piano-imitating instrument which has poorer quality sounds and wastes electricity, an insult to the piano. Obviously for these reasons it is used in rock bands.