I don't hear anything asian other than the language

Hmm it doesn't sound Asian to me at all~

Usually Asian instruments makes it sound really Asian, but there's none in this song~

^ I agree, instruments usually give some songs an Asian feel, but Aishou doesn't have that.

I have seen the PV a lot of times already, so now I do associate it with geisha, Japanese stuff. But the song alone doesn't really do that imo (aside from the language of course).

Hmm, this is kind of difficulat to answer, actually.
The instruments give the song a very western feel, but the melody and singing is more typical for Japanese (modern) pop songs. It doesn't really remind me of anything ancient or traditional Asian music though.

So I guess my answer is... Both? Haha, I don't know. Sorry I couldn't help more x3

Yeh, no. It's nice but I've never really listened to it again after the first time. My ears have better things to do lol