"Just loving each other a bit too aggressively..."

"I am 4.5 years older than my sister and when she was about 3 months old I sat on top of her in the baby swing because I wanted to swing, too! It wasn’t fair that she got an inside swing and I didn’t."

"I was born with a headful of thick, jet black hair. My sister was just 13 months older than me and very jealous. My mom would leave the room and then hear me scream. She couldn't figure out what my sister was doing until she caught her in the act of biting me on my head... where my mom couldn't see a mark because of my hair."

[I am... terrified and impressed.]

"My 8-year-old calls my 10-month-old a bonehead and rolls her eyes at her several times a day. She's taking the 'emotional insults' route. The baby laughs at it though, so it's backfiring."

"My mom said I tried feeding my sister a mixture of Kaopectate and Nair when she came home. ... [My best friend is the youngest of three, and when she came home], her sister put their dog in the crib and told the dog to eat her."

[FYI: I asked. The dog didn't harm the baby and certainly didn't eat her, because he's a good boy.]

"We were in Target a few weeks after I had [my son] to pick up diapers and stuff, and my 3-year-old kept asking if we could go to the Customer Service desk. I thought it was weird but we kept doing our chores. As we passed Customer Service on our way out, she got upset and kept trying to herd me back. I didn't understand but I noticed she kept staring at [her brother], who was in his infant car seat. That's when I realized she wanted to return him. We had a conversation about some very big feelings in the car."

"My oldest just straight up ignored his younger brother for the most part for three months and acted out a lot. He wasn't yet 3 when his brother came along. They have a great relationship most of the time now, almost three years later, but it was rough transition for a long time."

"I have the opposite problem. My younger one terrorizes my older child."

"I am five years older than my brother. Every time we got in the car I asked if we were bringing him back to the hospital (for like a year)."

“One of my twins loves the new baby. The other one acts like I brought home a rabid raccoon.”

"When I was a baby my older sister filled the playpen I was in with stuffed animals. She claimed she was giving them to me to play with but my mom is pretty sure she was trying to smother me."

"I had to buy a second Rock 'n' Play because [my older child] wouldn't stay out of it."

"Apparently when my mom brought my baby brother home I told her to 'Put him back.' That didn’t happen."

"My oldest literally ignored my middle child when we brought him home. It took around two months for her to acknowledge a new person in the house. She was very verbal, but I'd tell her to say hi to the baby and she would give me a look and walk away."

“She’s only 16 months older, but looks like she knew her life was changing...”

"My middle child tipped over the car seat the day we brought our youngest home. Baby was on the floor in his car seat as hubby was helping me get comfy on the couch and my middle child straight-up evil-laughed and tipped the car seat backwards!"

"While I was nursing the baby would cry, didn’t know why until one day I noticed my 3-and-a-half year old was squeezing the baby’s foot the whole time! Also, once kids were in car seats and I closed the door to go to the drivers seat, my oldest would scream at the top of her lungs to freak the baby out. Fun."

"I left my 2-year-old in the nursery with his 6-month-old brother for a moment to bring an empty bottle into the kitchen. I'm out of the room for mere moments, and I hear, 'Teddy's a horsey. TEDDY'S A HORSEY!' I sprint back into the room to find the toddler bouncing up and down on his brother's back. Thankfully the baby thought the whole thing was hilarious and was laughing away under his brother's bouncing bottom."

“When I was pregnant I took my boys, then 5 and 7, to a gender reveal ultrasound. The baby wasn’t laying right and my oldest kept saying ‘When’s my brother gonna move?’ The baby moved and the tech said ‘It’s a girl!’ My oldest, in a completely scathing tone said ‘It’s a GIRL?!’ and he walked out of the room. By the time she was born he was properly obsessed with her though so it all worked out.

“When we told my daughter she was having a sibling, she said she’d rather have a puppy.”

“I tried to mail my sister when I was a kid. Got her outside with stamps in a bouncy seat and the mailman rang the doorbell...”

“When my Mom was about ready to have me they asked my sister what to name me; she sat there contemplating and said either Wallpaper Paste, Rocket Fuel, or Horse Poop. They asked why those names and she said ‘Well those are some of the yuckiest things I can think of”. She was 4 at the time. Thankfully they didn’t choose any of her options.”

“My middle child was 13 months old when she came to the hospital to meet her baby brother. My husband was holding her and she leaned forward and grabbed onto the front of his onesie and tried to lift him up by the shirt.”

“My daughter was a week shy of being 5 when her brother was born. She came into the hospital room, looked at him and said ‘blah, blah, blah!’, like Dracula from Hotel Transylvania. A few days later I get an email from her kindergarten teacher congratulating us on the birth of baby Chase. The baby’s name is Greysen. Apparently my daughter liked the name better so she was telling people that was his name!”

“My son was 4 when his sister was born. Whenever she cried a lot he asked me when she could go back in my belly.”