OK, I know the answer to this whole thing. A friend of mine some 14 years ago ran into a somewhat similar situation.
This woman went WAY out on a limb when she pressed her ass against him. She apparently had already made her intentions known even before that incident.
When she pressed her ass against him, she wanted a reaction RIGHT THEN. Not necessarily sex right then...but an indication that he was on board with the idea. More than likely...when he DIDN'T react RIGHT THEN, she felt rejected and in her mind decided that she no longer wanted him.
Once a woman feels scorned or rejected, then all bets are off. When your buddy finally decided to make a move...it was TOO LATE. By then she had already decided that even if he decided that he wanted to do this thing, then she would embarrass HIM...and that's exactly what she did.