Nowadays mouseplay means to take a breather from work and to escape your boss it comes from the popular expression "when the
cat's is away, the mice will play."
Mouseplay stems from the original usage by Shakespeare in '
Henry the Fifth,' in 1599 - "Playing the mouse in absence of the
cat" (Act 1, Scene 2, Page 6, line 195). Older versions include the Latin proverb - "Dum felis dormit, mus gaudet et exsi litantro" – 'when the
cat sleep, the mouse rejoices and exits the hole' and the French version - "Ou chat na rat regne" -
'Where there is no
cat, the rat is king'