Is this done in China or Cuba?
No, never done in China. Lived there more than two decades.
I don’t know about China or Cuba, but when discussing this issue with a friend, they told me many year ago before AIDS they knew of a swingers’ club that had exactly that practice. In case any one who attended developed a venereal disease they were required to call the club to contact trace the people in attendance at the same time the sick person was there. These folks apparently believed in living free, but not stupid.