I get it. The breast is a sexual part of the body as well, but we make too much of women feeding their children. When its used for feeding, why can't we just ignore it. Most women will cover up out of a sense of modesty. For those that don't do such a good job of that, don't impose your inability to separate the baby's needs from the sexual thoughts in your own mind as a reason to make these people feel bad. They are feeding a child in a natural way. Gentle encouragement to use a blanket is about as far as you need to take it and I would argue that in most cases that isn't necessary unless the woman is leaving things out for excessive periods of time in a very public setting.
BG