Your brother, as a birthday wish

"-- happy birthday to you!"

We finished singing, watching as my newly 18-year old brother Greg blew out the candles on his cake. A slight tingling sensation went down my spine and I shivered, but it was the middle of winter, and a particularly miserable day at that, so I assumed it was only a chill.

"Oh I can't believe it, now my son's are both all finally grown up!"

Our mother beamed, tears welling in the corner of her eyes.

"So did you make a wish?"

I asked Greg. He didn't reply at first; he was staring out the window. Half a second passed and his eyes grew wide before he stammered:

"Y-yeah I did, Max. Wow."

The last word he mumbled more to himself than anything, still staring out the window even as our dad went to close the blinds. I was thankful for that, the sun was beating in and on a scorcher like today I appreciated all the shade there was.

"Well then let's get to the cake, I'm starving!"

I joked, snapping Greg out of his trance. He whipped his head around, wildly looking around until his eyes fell on mom. More specifically on her chest. A look formed on his face I hadn't seen from him before, but I realized that it was lust.
Weird, I thought, that's our mom, and it's not like there's even much to look at there anyways.
Our mother wasn't the most well-endowed woman by any means; her chest was fairly flat, with two barely B-cup breasts despite having had two kids. Her ass as well was nothing to speak of, she had good hips and a hint of what could be a good butt if she worked on it, but it wouldn't make anyone do a double-take. I surprised myself with my thorough internal analysis of mom's body, but not as surprised as what Greg said next:

"Actually before we do cake, shouldn't I get my blowjob?"

Mom gasped and I was taken aback as well. How could we have forgotten about his blowjob?? It was his birthday after all. Mom quickly dropped to her knees, her hands undoing his jeans and fishing out his dick.

"Oh I'm so sorry baby, let mommy make it up to you."

She began sucking in earnest, her head bobbing back and forth madly, filling the room with the sound of her slurping. I began to get hard, remembering the blowjob mom had given me on my 18th birthday too. How she had all but swallowed my cock before letting me cum on her tits. The same tits, in fact, that she was pulling out of her shirt now. The sight of her massive knockers on display definitely started to make me horny, especially now that she was squeezing and groping them, moaning around Greg's cock. Greg now held her head with his hand, fucking her throat while mom sat on her knees playing with her E-cup boobs. Her fat ass filled out her yoga pants and jiggled with Greg's hard thrusts to her mouth. He threw his head back and groaned, holding mom's head in place as he buried himself to the very back of her throat. Mom gulped down his cum as he pulled out, ropes connecting the head with mom's lips.
Turning to me, I felt the same chill as before when Greg said:

"Why don't you come clean me off Maxi."

I almost squealed with delight and dropped down to my knees as well, taking his thick dick in my hands. I stuck out my tongue and licked it, a moan escaping my lips as I tasted his load. Mom came up behind me and pulled down the collar of my shirt, freeing my big titties. I sucked on Greg's cock while mommy played with my chest. I was definitely reminded of my 18th birthday now, and the blowjob that mommy and I had given then together. We had gone out to a bar, found the hunkiest guy there, and spent the whole night swapping his many loads of cum between us. Her hands made their way into my pants, her fingers brushing against my clit which made me moan and gobble up Greg's yummy cock more. My pussy was so wet now, and the feeling of mommy's naked tits squished into my back, as well as her fingers inside me, drew me closer and closer to orgasm. The tipping point was when Greg, without warning, shot his seed into my mouth. I came hard as well, trying my best not to swallow the whole load despite how good it tasted. I pulled away and twisted around, kissing mommy deeply while I shared the contents of my mouth with her. In turn, she pulled her hand out of my pants, and stuck her fingers coated with my own cum in my mouth. The taste of my brother and my own juices on my tongue nearly brought me to another orgasm, and I greedily swallowed, licking mommy's fingers clean to get every last drop of myself off.

"Get up and bend over Maxi, I want to try out your pussy."

Greg said, hauling me to my feet. I giggled and wiggled my jeans over my fat butt, making sure to stick it out towards him as I bent over to push my pants past my feet. The weight of my big fat boobies hanging down felt really good, and I squeezed them together while I waited for Greg, still bent over.

"Like, come and get it birthday boy, my pussy is all for you."

I cooed, twerking my ass in his direction. His hands grasped my hips, holding me still while he lined himself up with my hot slit. I could feel him poking at my entrance and as he slid in I saw fireworks. My knees almost gave out, the only thing that stopped me from crumpling to the floor was Greg's strong hands holding my up and firmly planted on his cock. My eyes rolled as he thrust into me, every push better than the last. Dimly, I was aware of mommy sitting at the table, working the double-sided dildo we call 'Daddy' in and out of her juicy pussy. I was lost in rapture, having came so many times I'd lost count. After what felt like both forever and much too soon, Greg slowed his on my sex.

"I'm going to cum soon Maxi, how do you want it?"