Play to their 'friendship'

"Edelgard," said Henry. "We're friends. Friends don't make friends do anything uncomfortable. As your friend, I don't want you to do anything uncomfortable. So, here's what we'll do. When I wake you up, you'll be refreshed, relaxed. You'll remember having a good time in your session and tell the others in the Black Eagle house--or any other house--what a good time you had and what a big help I was. Preferably the girls."

Edelgard nodded.

"When you wake," Henry continued. "Any time I say 'As a friend, I think you should' followed by a command, you'll do the command because that's what friends are for. As long as it doesn't make you feel uncomfortable in any way."

Henry could always lower her comfort levels later after building up more rapport with her.

"Understand?" he asked.

"Yes...friends do what friends say," Edelgard mumbled.