Go out in Yukata!
I would recommend to enjoy Hanabi (fireworks), popular summer event in Japan. Since you wish to enjoy Japanese summer style, find a nice “yukata” for yourself to truly enjoy Japanese summer! Don’t forget to enjoy some “Kakigori” (shaved ice), “Ramune” juice(lemon pop juice) and “Watagashi”(cotton candy) while you enjoy beautiful fireworks in the night sky. “Uchiwa” (paper fan) may be a good souvenir for your friends in such an occasion.