A more advanced bachata couple will be very close and comfortable with each other to be able to do complicated moves like this that require a lot of trust. The woman is relying on her partner to hold her up and is comfortable enough being this close
Via www.sharonmdavis.com: “Swing dancing” is an umbrella term for any dance done to swinging jazz music from the 1920s, 30s or 40s. The most popular (and spectacular) of these dances was the Lindy Hop - a partnered dance that evolved out of the Charleston in the late 1920s, in Harlem New York. It is named after aviator Charles Lindbergh (1927 newspaper headlines read “Lindy Hops The Atlantic”). It is sometimes just called The Lindy, and some parts of the world knew it as The Jitterbug.