Whenever someone says this kind of thing I tend to look at the picture with more focus to find out why you would say such a thing.
I think in this particular situation, her body is reacting chemically against her will. It's the same as tickling a girl for extended periods may give her fits of laughter that continue even beyond the tickling itself, but she's not exactly happy regardless of the reactions.
She's feeling pleasure, the lactating of the breasts shows this (an intense, but deep sensation) but it's all physical, there is no willingness here. Though who knows how long that will last.