who is Reimu's pillow ?

Looking closely you can see green hair and a red bow, which more or less excludes anyone but Hina, even though the exact hairdo is not 100% consistent with the usual depictions (but then, they're drunk, and anyway people don't wear the exact same outfit and hairstyle every single day of their entire life).

Fairy Juice, that pretty much freezes all logical thinking

post #722750 and that was just water before

The Blue Fairy. It's like Absinthe but cooler going down.