When they got to Lina's house, Lina discovered that no one was home.
"Perfect" said Lina.
Lina took Amy up to her room. Lina had decided that she was going to order Amy to do things that she would never do, even for a prank, in case this was a prank that Amy was taking too far.
"Alright, I want you to, umm..., strip until you are naked."
Much to Lina's surprise, Amy did this without hesitation. Amy would never get naked in front of her best friend, would she?
"Um, good." said Lina, "now, um, start playing with yourself."
Again, Amy did so without hesitation. Now Lina knew that this is no prank, Amy is now really her slave. Now what would she do?