LOL for the PV, it's kinda~
I think that's because this line :
Spoiler:
Letting you play with my fingertip
Running all over your body
Below the centre, below the centre
So that it slips, it slips
Our eyes met
Then suddenly below that, below that
You trailed a series of kisses
Translation from
Channel-Ai Blog 
That's why
Ai Love Otsuka 