“You’re like a dog with a bone!” he exclaimed, utterly fed up with overwrought euphemisms. 
“So?” asked Anya, who was obviously frustrated of a different kind. 
“So, it’s my bone! Point of fact, it’s Buffy’s… whether she ever uses it again or not.”

When Spike sets Anya straight on a few things, she decides to help him out (Season Seven: Get it Done).