Today, BS might be leaning more towards a body-on-body, with some girls not even offering that. For example, Amber's BS leans towards a Russian style, thanks to her pair of 36C huge & round melons.
Sarah is probably one of the few girls in this market who can truly provide a genuine BS, thanks to her petite and flexible body, as well as her voluptuous curves. A standard BS should start from the back, with the body gliding over every inch of your skin like a ribbon, tantalizing your senses and achieving an ultimate allure. I reckon this kind of experience will become increasingly rare to find in the market.