Akihabara UDX building underground parking is wellknown as sanctuary of ita-sha and many ita-sha gathers not only holidays but weekday.
One summer day 2016, Shokaku and Zuikaku ita-sha which Shokaku met at Himetama itasha festival were shot at there with Haruna itasha and kigurumi Shokaku and Haruna were invited the photo shooting.
Here were links of Akihabara UDX building underground parking official site which their photos were opened.(Japanese site)