It’s Japanese National Holiday, Kodomo no Hi (Children’s Day).
Although the direct translation of Kodomo no Hi is Children,s Day; it is for Boys Day.
We decorate family carps, Kabuto (Japanese Samurai Armor), and etc to wish for health and prosperity.
In addition, we take a bath with Shobu (iris) to wish for winning.
The Iris, Shobu pronounces same as battle.
Taking a bath with Iris brings a health to win the battle.
And I surely want to win against COVID-19!
Choco is a boy so he takes a bath with this, too.