In order to achieve the exposure you want with ease, you need to get a feel for the luminous power of the particular light sources that are in play when you are shooting. I think this comes pretty easy once you have a look at the numbers because then you see that there are worlds of power between the various kind of light sources, even though our naked eye would not signal us so much of a difference.
For reference: 1. The boudoir photo eBook with the bed scene: http://boudoir.cc (NSFW) 2. The BTS video of the shoot: http://youtu.be/Ph5j8i9iTp4 (Kind of SFW YouTube version)
