Hiroyuki likes to twist common hentai element into pretzels, no? First than NTR with the ending that made you wonder about the whole situation, then that strangely heartwarming three way, and now this where we border on declaring the female lead a tsundere in love. At least these aren't boring.
I like how the first thing that came to his mind when she said "Anything" was touching her breasts. He definitely knows his Hentai situations and how to use them.
...I wonder if her friends knew, though, by that ending.
I'm pretty sure they knew what the two were doing but decided to go along with the beating story - at least their facial expressions gave me this impression...