Imitate
You try to use your fingers to cast doubt on people by using them to imitate each other. Right now you're using your fingers as finger puppets, imitating one of your friends to the others.
Picture your angry friend standing up next to your fingers, shouting, "I'm the real me! That's just an imitation!" The rest of your friends look nervously at each other. They doubt this person is real now.
ぎ
まが, もど
None
Everyone thinks the friend you were trying to imitate is the imitation now and they have them in a guillotine (ぎ). You even doubt if they're an imitation or if your fingers are the imitation.
Okay, so that's a lie, Your fingers are definitely imitating them, but you don't want to end up in the guillotine so you keep your mouth shut.