Moving in with my sister

I'm John. I'm 18 year old sophomore in college. I'm 6' and about 180.
My sister Cara is 25 married with a 2 year old and a 6 week old. Her husband is a truck driver and never home.
Our parents are in an ugly divorce so my sister is allowing me to stay with her.
The first night was crazy. My 2 year old nephew was hyper and the baby Lisa was crying constantly. I was trying to be helpful while moving my stuff into the basement.
I got my bedroom set up and asked my sister what can I do to help.
She asked if I could put my nephew to bed while she tries to get the baby to sleep.
I laid down with my nephew in his bed and we watched a movie till he fell asleep. I could still hear my niece crying. So I knocked on my sisters bedroom door which caused it to open just a Crack. I could see my sister trying to get the baby to breastfeed. She wasn't. She only screamed.
I went to the kitchen and made the baby a bottle. I took it to my sister. Who was sitting in her bed crying because she was tired and frustrated.
I took the baby, trying not to stare at my sisters huge titties. I offered the baby the bottle and she started drinking it right away.
I stood there at my sister's bed feeding her. While staring at my sisters at shirt wishing I could stick on her titties. Baby Lisa was asleep in minutes.
I asked my sister where she wanted me to lay the baby. She was still crying, she had pulled her shirt down but her breasts were leaking milk and wetting her shirt.
My sister asked if I could take her to my bed so she could shower.
I said sure.
I took the baby to my bed in the basement and I laid her down on the far side of my bed closest to the wall. I didn't want her to fall off on the edge.
I laid in the middle patting her side while I hummed to her.
I dozed off but woke up when I felt the need move and hands on my shoulder.
I opened my eyes and saw my sister . She smiled but was still crying.
"What's wrong?"I whispered.
She smiled "my pump broke, I'm engorged and it hurts" she spoke softly.
I rolled onto my back with my sister sitting next to me with one leg on the mattress hey other foot on the floor.
"Can I help?" I asked.
She shook her head side to side and wiped a tear from her eye.
I scooted over more towards the middle of my bed and my sister laid down on her side.
I turned and faced her. Her wet shirt brushed against my arm.
I learned up and kissed her forehead then I kissed her cheek. Then I kissed her bare shoulder. Then I kissed her arm. I kissed her tittie through her shirt. My cock was hard. I tried to hide my erection but I was so turned on.
She inhaled sharply. I sucked her nipple through her shirt. She pushed me back. I told her "I'm sorry. I was hoping it would help".
My sister slowly lifted her shirt over her head. She laid on her back. I propped up on my elbow and licked each nipple. Then I sucked one nipple into my mouth.
I sucked and my sister's milk sprayed in my mouth. It was sweet and warm. I sucked a few more times and my sister grabbed my head and moaned "yeeeessssss". I sucked harder.
My cock was throbbing. My sister was breathing deep as her fingers ran through my hair as I sucked and sucked more of my sisters breast milk.
I don't know how long I was humping my sister's leg. But I realized that I was. My sister stuck her finger inside my mouth to break my sucking. She quickly offered me her other nipple. Which I quickly sucked into my mouth. My sister moaned again as I sucked her milk.
My sister reached down and tapped my thigh. She whispered " move between".
I didn't stop sucking my sister tittie. But I raised my hips and settled between my sisters legs.
My sister began rocking her hips. I moved my hand to her thigh. I squeezed her thigh.
My sister moaned and arched her back. I inched my fingers closer to my sister's panties.
I pressed my fingers against my sisters lace panties. They were wet and the heat coming from my sister's pussy was intense.
I moaned in to my sister tittie.
I slid my sisters panties to the side and my fingers slipped inside.
My sister's pussy was smooth with only a small patch of soft hair on her pelvis. My sister spread her thighs causing her pussy lips to spread. My finger ran up and down my sister's wet hot pussy. Her pussy juice made her pussy slippery.
I used this advantage and slid my finger into my sister's pussy.
My sister inhaled and moaned "yeeeeesssss. Oh my God Yes!".
I sucked harder and I moved my finger in and out of her pussy. I added a 2nd finger in my sister's pussy.
My sister moaned "fuck me please".
She didn't have to ask me twice.
I kept sucking as I pushed my pajama pants down to my ankles.
My sister pulled my mouth off her nipple and pulled my face to hers. She kissed me. Her tongue danced with mine as we both were panting and couldn't get enough. I slid my sisters panties to the side and I pressed my cock head between her pussy lips.
I felt my sister's pussy stretch around my cock. She inhaled and turned her head breaking our kiss "Holy fuck John you're huge" she hissed as she clutched my upper arms.
I pushed my cock deeper feeling my sisters pussy stretch around every inch as I pushed deeper.
My sister buried her head into my neck and she sucked my neck and she moaned.
I began to thrust in and out steadily. Not wanting to hurt her I hadn't sank balls deep.
My sister was beginning to moan louder as she her mouth to my ear and she said "fuck me John. I want all of you". She wrapped her legs around my waist.
I thrusted again pushing more of my 9 inches in her pussy. My sister body began to quiver and her pussy began to throb around my cock. The way her pussy was thriving it felt like she was milking my cock.
I couldn't hold back I thrusted harder, deeper. My sister cried out "fuck me fuck me fuck me" so I did.
I began to fuck her hard and fast. Watching my sisters titties bounce with each thrust was turning me on even more.
I moaned "I'm gonna cum sis, I'm gonna cum". I pushed against hey to pull my cock out of hey pussy but she tightened her legs around my waist.
"Cum in me John cum in me please John please breed me" she moaned.
I started shooting my cum deep in my sister pussy. At this time my niece started crying. My sister kept her legs wrapped around me. She reached over and picked up the baby.
She let the baby nurse. On one tittie. My sister smiled and whispered in a very sexy voice "she can't drink me dry, don't you want to suck some more?"
I leaned my head down and started sucking my sisters milk from her tittie.
I felt my cock throb while still in side my sister's pussy. My sister started rocking her hips rubbing her clit against my pelvis as my cock began to fill her sloppy pussy. Each thrust sounded wet and sloppy. The smell of pussy and cum filled the small basement bedroom.
I rocked with my sister's rhythm as I sucked her milk while my niece sucked hey other nipple.
My sister's thighs began to tighten around me. I ground my pelvis harder into her clit.
Her pussy began to throb around my cock. I sucked her nipple between my teeth and moaned as my cock shot stream after stream of my cum in my sister's pussy.
I slid from my sister's thighs. I released hey nipple. I was panting, she was panting. My niece was still sucking her nipple. I rolled off the bed and went to the bathroom. I showered. When I got back to my room my sister and the baby had left my room.
I felt sad but excited as I hope I get to fuck and suck hey again soon.