Let me give Du some examples;
1) In "fool for love"
2) In "chosen"
3) In "the body"
4) In "helpless"
5) In "becoming part 2"
6) In "i only have eyes for you"
7) In "seeing red"
and many others
I don't know if I am right. Maybe it is something that Sarah Michelle Gellar does oder Joss Whedon's instructions oder something that happens spotaneously.
It seems strange to me. I don't think I like it. I find it a bit silly.
Is it on my mind oder Du noticed that too?