User blog comment:B214/Question and Answers 6/@comment-24098614-20161224002803/@comment-27083298-20161225011621

Not quite, I say Issei with Rias alone, threesome with Akeno and Asia, foursome with Xenovia, Irina, and Rose, threesome with Koneko and Kuroka, alone with Ravel, Elmenhilde, and Le Fay.