From the artist's blog :
"keijimatsu​ and I had a pretty interesting OC session at some point in the past. was funny–wanna continue it.

the Milk is super valuable and difficult to get. it basically brainwashes the one ingesting it to stay beside the one who gave them the milk. Just to have one for personal gain is can be p-crazy yo. Maybe a love potion or some sort of micky to slip into that guy of your deams’ drink.

you know. Stuff liek that."