" You can do whatever you want to me ...... or something like that ........ " , Hiura's own words.
Hiura's words are broad and ambiguous enough to include an offer implying a activity with a sexual connotation to it. Whether or not sex is going to happen is placed upon Midou, and how he decides to respond. But what does Midou select for this one time and unique birthday invitation ? Sex ? No ! His highest and most desired activity with Hiura seems to be of a fashion and style nature, centered around makeup and clothing presentations. Thus, the mangaka gives us an interesting perspective on the two character's interests and priorities closest to their hearts.