Then I'll go ahead and explain everything.

I used contagious magic as the incantation's foundation.

Contagious magic... "Once touched, it will continue its influence even upon separation."

Inserting hair and nails into a cursed straw doll is a certain variety of this magic.

Well, the cursed doll itself is a form of sympathetic magic. It's a hybrid spell.

So, in the case of this drug...

It remembers the identity of the last person to touch it.

In other words, right now it remembers me, its creator.

Onto the drug's primary effect.

Upon intake of this drug, it will forcibly give the subject an interest and fascination with the one the drug remem—

That's too much! Give it to me in three lines!!

My, what a shame. If you're bored, why not listen?