"All of us are part of Remus’ pack so we all have a bond with each other. Some bonds are stronger than others within the group, but if one person is feeling strong emotions, sometimes we can all pick it up. It’s a lot more straight forward when the pack is comprised of blood relations, but ours is a little more complicated. Right now, Hermione is royally pissed and she’s projecting into the bond. Another added component is that those emotions can either be intentionally or unintentionally pushed through."