D.R.
hi danielle, i havent had the same exact experience, but i have "disciplined" all my kids around this age for things like biting me while nursing or banging their heads, they seem to try both those things around this age. what i find really works is to give a quick stern "NO." with an angry face and then turn completely away for a minute or 2, or walk away if you can do so safely. in your situation, i would do the stern no, and then pick up her brother and walk away, leaving her all alone for a couple of minutes. i think if you do this right away, it should work pretty quickly, it always did for me. i would want to get rid of the biting thing asap. good luck, D.