July 7th is Tanabata festival, an event that originated form the legend of two stars called Ori-hime (Vega) and Hiko-boshi (Altair).
It is believed that your wish will come true if you write it on the Tanzaku (strip of paper) and hang it on the bamboo sticks. You can write your wish on Tanzaku paper by the bamboo.
The priest will pray all of the wishes on Tanabata ceremony on July 7.