A Toddler's Guide to Daughtering Your Parents, Big Sister Edition
When your mother and father bring home a four hour-old baby and announce that she is going to stay, make sure the baby knows her place by only referring to her as it, as in "I want to hold it". You can also try telling the baby's great-grandmother to "keep it" and see if that works.
When all of a sudden you have to share your mother's breasts, and the baby always seems to get to nurse first, tell your mother, "I need nursies to grow too!". This should weigh heavily on her conscience.
It is useful to fill the baby's things with your toys, as in marking territory. It used to be yours anyway, so technically it still belongs to you. For example, the bassinet should be full of stuffed anumals at all times, as should the swing , the bouncy seat, and the bucket carseat. That way, it is a pain for your mother to put the baby down at any time, and she will remember how sweet and trouble free life was before she brought "it" along.
Whenever someone brings a stuffed animal for "it" make sure it ends up in your possession by exclaiming "thanks! I love it! Boo-ful aminal" to the gift-giver. This makes the gift-giver feel appreciated, and it gets you the toy. After all, one wouldn't want to spoil "it", would one?
Whenever "it" is asleep is a good time to use your outside voice. This wakes up the baby and flusters your mother, again reminding her that life was easy when you were an only child.
Insist that your dollies be cloth-diapered. With the cute diapers, not the prefolds.
When your mother is ready to take you on an outing with the sibling, and she and the baby are ready to go and you are in your snowsuit, announce that you cannot go ANYWHERE before nursing your teddy bear. This buys you time before you have to be in public with "it" and withstand the endless "oh isn't she cute?" remarks. Off with snowsuit, off with boots, nurse the bear, and then reluctantly agree to get dressed again to go on the outing.
When taking baby to endless midwife/doctor's appointment, make sure you are not forgotten. Bringing a stuffed animal is useful Eeyore gets weighed and examined, the nurses think you are the cutest thing ever, and people end up paying as much attention to you as they do to "it". After Eeyore has been weighed and examined and the doctore feels it's time to examine "it", there are several things you can do to bring attention to yourself. Climb the windowsill. Stand up on the chair. Knock down the paper-roller that is attached to the examining table. Your mother, in an attempt to divert your attention, will then allow you to play in her purse. At this time, it is recommended to put her coins in your mouth. This really gets her attention away from "it", and you are at the doctor's anyway so what can go wrong? At the next visit, she will remember to bring dad for you to play with.
When your mother decided to try the decidedly unwise tactic of the "naughty step", enthusiastically go on the step and exclaim "mummy I love the step, I love it". She'll never put you on it again, and she will stop taking advice from a nitwit on television against her better judgement.
When the baby is going through a growth spurt and must be nursed endlessly, ask to watch Lilo and Stitch. Over and Over and Over and Over again. Until she gives up on nursing the little beast just to get anything else going through her head than Lilo and Stitch.
When your mother boasts that "it" sleeps very well during the night and comments on how well rested she is, it is important to not deprive her completely of the newborn experience. Set you inner clock for 3 AM and have a few wails. You do not even have to completely wake up to do this. She will be so happy to feel like the other mothers of newborns and she will have you to thank for this feeling of belonging.