I'm confused :-) I haven't downloaded any hack for feeding babies (in fact, nothing baby-oriented that I know of). I do have the InSIMenator (and the Inteenimator), and a number of other hacks I've had for a while. Today I discovered one of my sims, who's just had a baby, breastfeeding her baby. I've never seen this before. It turns out when she's holding the baby she has a 'feed baby' option which sets her breastfeeding (she appears to do it endlessly until cancelled!), but it doesn't seem to be available to other mothers with babies.
Where did this come from? Has anyone else seen it? Why is it not available for all mothers? I've searched the forums, and seen requests for this feature, and references to a 'nurse baby' hack, but I don't have that. But I seem to have this option without having asked for it (I think it's neat, by the way — the animation isn't perfect, but it's pretty good).