Screw my sister for mothers day!! she dont deserve anything?

This Sunday is mother’s day my mom ask me what im getting my sister for a mother’s day gift. I told her not a dam thing. My sister and I don’t get along last year my friends and I was chilling we were just board we thru her babies pampers out of the window shooting hoops in the back yard dipping them in the pool. She got mad because of that. I caved in and replaced them I shouldn’t have to buy them but I did it anyway. Since then she moved out has her own place now. When she come over to visit she on my *** telling me why I don’t help my mom clean the house, Do my own laundry, she calls me a free loader a spoil brat, a Gerber baby, the best is she tells my mom calling me little boy is an understatement that im a baby. She always has to say something when she comes over. She just cant keep quiet and shut her hole. I admit when she says those things to me I get mad I get even she leaves stuff for the baby over my mom house. Car seat stroller, etc and Ill put shoe polish on them or put them outside when it rains. I ask her to buy me a game for ps2 a few weeks ago she tells me know ill buy you a fisher price toy instead. I shouldn’t have to buy her anything its not written in stone and I cant remember the last time she bought me anything I can use or need. I shouldn’t be obligated to buy her anything right?