"Ai Ai Gasa" (アイアイ傘) is the third single by the Japanese duo Tegomass, released on June 18, 2008, by Jonny's Entertainment.
It was used as the ending theme for the anime Neo Angelique ~Abyss~.
[2] Literally ai ai gasa (相合傘) means to share an umbrella,[3] but it could also be read as "Love-Love Umbrella", as the word for love (愛) is also pronounced ai.
As such, sharing an umbrella as a couple in Japan is considered a romantic expression, and teenagers often draw an umbrella with their name and the name of their crush, the way one would in a heart.
In Tegomass's video, the two are creating rain to make a young boy and girl walk under an umbrella together.