At longer exposure to the drug, a victim may be prone to a phenomenon Lucius dubs "indoctrination", resulting in the victim literally becoming a slave of the one who has poisoned them. In Lucius' case, anyone who has drunk the potion will grow a certain affection towards Lucius; they will follow his every command, and will view him with superstitious awe. Lucius himself claims that the indoctrination is "merely" a side effect that Lucius did not anticipate when he created the drug.
The use of Sunshine milk is shown for the first time when Lucius drugs Barden Frey in his own keep. As a result, Barden becomes manic and completely relaxed but also notes that he is in a state where he is "enchanted and terrified". Lucius also allegedly used sunshine milk on the Kogathi pirate Vyran.
For a brief time, Lucius had been exposed to sunshine milk after Lanna Ashford drugged him with it, believing it be milk of the poppy, and then proceeded to rape him. This caused Lucius to be prone to long-term hallucinations, even after the potion was worn out. After this, Lucius killed Lanna, but also became more mentally unstable, causing him to leave Westeros after being convinced that his own mind was out to destroy him.
As of recently, Lucius Dragen has managed to create a second version of the drug, which comes in a solid, powdery form. Lucius frequently uses this form of the Milk to quickly subdue and control victims more decisively, although in this form, the drug will have worn out quicker.
- Sunshine milk is partially based on Scopolamine, a terrifying hard drug that shares many of Sunshine milk's effects.