Let me give te 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 o Joss Whedon's instructions o 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 o te noticed that too?