She knows it’s not Buffy.
She tells herself it’s just a machine which happens to look like her dead friend.
But on a night when Dawn’s run off to Spike’s crypt, and Tara’s away in Boston getting another part of the ingredients for that spell, she gives in.
Back in high school (before they’d blown it up) she’d once woken from a vivid dream, her long red hair tangled, her body sweaty and needy. Dreaming about Buffy. Her body, her moves, her poise and grace in the fight.
But it’s night. She’s alone. And she misses having someone to cuddle up to in their double bed.
She tells herself that it means nothing, and turns the bot on.
Two hours later, she screams her way through her fifth orgasm and her mind can no longer tell the difference between Buffy and the blonde haired figure kneeling before her.