1875, Anthony Trollope, Miss Mackenzie, Norilana Books, page 122:
"It's not as if you two were young people, and wanted to be billing and cooing," Lady Ball had said to her the same evening. Miss Mackenzie, as she thought of this, was not so sure that Lady Ball was right. Why would she not want billing and cooing as well as another?
(Can we find and add a quotation of Thackeray to this entry?)