Although Rachel didn't fight, the sudden rush of so much pleasure at once made her form shift to some degree in an attempt to keep her form straight.  She whimpered in sweet pleasure, bucking her hips to give Luna more to taste and trying as hard as she possibly could not to just cry out.  It was driving her crazy, and she needed so much more, but she couldn't think and didn't want to try too much more in order to break what seemed to be a need for Luna to assert dominance.  She was already so very wet, and even though she didn't taste completely normal, there was a gentle sweetness to her nectar that seemed to prove how badly she needed this.