E.K.
Does your younger daughter suck her thumb or pacifier? If so this probably has something to do with it. Your older daughter may be looking for attention, positive or negative. She has found something to get you to watch her and give her your attention. Try spending special time with her, alone and see if this helps. Also, talk about how babies suck thier thumbs, fingers, pacifiers, etc...not BIG girls. Good luck. If you have any questions let me know...you can email me.