Using her friends to scope her out

Boris decided to use either Cordelia or Willow to get to Buffy. Considering Cordelia was probably too mentally strong for his mind control powers, he chose Willow.

He knocked on her door in his student disguise and she answered.

"Can I help you?" she asked.

Boris waved his hand in front of her face, putting her into a trance.

"Willow, when I wake you, you will believe I am your boyfriend. I am the sexiest man you know, and nothing I say or do is inappropriate, including asking about your friend Buffy's Slayer instincts and abilities. You will tell me all I want to know about those, because it is important to be honest in a relationship."

Willow nodded mindlessly.