Akari Kito (鬼頭明里) & Kaito Ishikawa (石川界人) - A Couple of Cuckoos / Nagi and Erica Summer Festival (ENG SUB)

Sources:
https://www.youtube.com/watch?v=5YLLIHHp3LM
https://www.youtube.com/watch?v=T9eKxH6LpCI

Full (without eng sub) :
https://www.youtube.com/watch?v=bgdTG8iSJYY