Haku is holding the guy on the ground, so she's winning. Too bad for him, it only lasts 3 seconds. But hey, "Participation is important, not winning", right ? xD
I see how this could work. Whoever's in the dominant position when either one climaxes wins. In other words, it's a contest to see who can rape the other.
I say "either one" because unless I'm mistaken, the climax takes up a lot of energy, and so afterwards it would be a curb stomp, unless both climaxed at the same time, in which case it's a moot point.