In 'Earshot' when the scooby gang are in the library finding out about Buffy's ability to read minds, watch when she's reading Wesley's mind. Buffy is leaning forward with her elbow on her leg and her chin resting on her hand. In one angle her chin is resting in her palm, in the next it's resting on the top side of her fingers, then it switches back to been in her palm. not very big but it's clearly visible.