Hi Liz!
You had said you were interested in some context for Lamia?
I highly recommend looking at Darla from Buffy and Angel, especially in the first 2 minutes of the Buffy episode Becoming, Part I (Season 2). I believe it is streaming on Netflix, which is the legal and most high quality way of seeing it, but if you want to go the illegal route here is a link: http://fastmegatv.net/buffy-the-vampire-slayer/season/2/episode/21#embeds. You just have to jump through some pop up hoops to get there. Just keep clicking on the large player until it plays. She is the ultimate alluring, mysterious predator.
Here is a video of about Inara Serra from Firefly whom Jenny was talking about last night. It is a fan vid about the character, but it discusses her companion mask and when it slips: http://blip.tv/stuffyoulike/30-inara-serra-doesn-t-have-a-clever-title-5912018. While I highly recommend watching the series anyway (it is only one season), there are a few episodes that showcase her companion skills like "Serenity "(around the 15 min mark), "Shindig," and "Jaynestown." Alas, no good clips from them exist aside from in fan music videos. Here is the best Inara one that I have found: http://www.youtube.com/watch?v=X4aS_gHJQFM
Here is also a link to the first episode of Lost Girl, a TV show about a succubus who feeds on the life force of people like Lamia does. At about the 2:11 mark there is a pretty fantastic feeding that might be interesting for you: http://www.dailymotion.com/video/xx0tej_lost-girl-season-1-episode-1_shortfilms#.Ue2deI1lRfZ Bo as a character is not very Lamia-like but her powers are.