Author's note: This story takes place after Avengers: Age of Ultron.
***
"Nervous?"
Natasha smiled softly, "Would you hate me if I said no?"
Maria returned the smile and wrapped her arms around Natasha from behind, "I could never hate you Nat."
Natasha smiled, "Well, isn't that cheesy."
Ignoring the dig Maria pushed, "Seriously though, are you still ok with this? Because we can still cancel-"
"God no! I want this." Natasha said firmly, spinning around in Maria's arms and looking her girlfriend in the eye as she continued, "I've wanted this for so long, and now I finally feel comfortable asking for it. Please, don't deny me now."
There was a long pause, then unable to resist Maria grinned, "You know damn well I can't deny you anything."
"There you go being cheesy again." Natasha grinned, before squeaking as Maria swatted her butt playfully.
Maria then stared lovingly at her girlfriend for a second, gave her a long kiss and then asked, "Sure I couldn't interest you in a butt plug? Maybe a little pre-game fisting to help you out?"
"No." Natasha shook her head, grinning wickedly as she added, "It's my first time taking an ass fucking from Wanda, and I want my slutty little back door nice and tight for when she busts it open."
Maria raised an eyebrow, and then smirked, "Getting into character I see."
With a smirk of her own Natasha leaned in and whispered, "Who ever said that insatiable anal slut wasn't the real me?"
"Because we are more than our most twisted desires." Maria pointed out, resting her forehead against Natasha's as she added, "And whoever you think you are, however twisted and nasty things get tonight, never doubt that I love you with every fibre of my being."
Trying and failing to hide her blush Natasha scoffed, "Well, you'd have too to be willing to arrange an anal gang bang just because your ass whore of a girlfriend requested it."
"It wasn't like it was hard." Maria scoffed, slapping Natasha's big butt and then squeezing it as she added, "THIS, is in high demand, and if you hadn't specifically wanted it to be all-girl, I'd have even more volunteers."
"What can I say, I prefer it when cocks don't go soft." Natasha grinned.
Maria rolled her eyes and then murmured, "Seriously Nat, are you sure about this? The threesomes and foursomes were one thing, but a gang bang?"
Becoming serious Natasha replied, "I'm sure. This has always been one of my biggest fantasies, even when I was a top. Now after everything that happened with Pepper, and with Jane... and with you, and nearly having everything I care about being wiped out by a crazy robot, I just... I want to do this while I still have the chance. The question is, you okay with it? Because you're the only one I really want, my partner, my everything. I love you Maria, and if this is too much-"
"Hey." Maria said, calming her panicking girlfriend down, "I love you. That means nothing is too much for me. Not ever. Not when it comes to you."
"Good." Natasha smiled, and then pulled away, turned around and stuck out her perfect ass, "Now, speaking of preparation... I wouldn't mind a rim job."
Maria smiled and lowered herself to her knees.
*
After about an hour or so of having her face buried in that glorious ass they had got dressed and headed to the main room. An hour after that Maria was still tasting Natasha's butt in what was now her third Martini as she watched their guests arrive. Natasha greeted every one of them, from the calm and confident Pepper Potts to the super nervous and jittery Wanda Maximoff, like the pro that she was.
They had been both trained in espionage of course, and if needs be Maria could make small talk with the best of them, but it was Natasha who really thrived in this kind of environment. Truly, there was an artistry to the way that Natasha Romanoff put everybody at ease, even Wanda, although it had to be said the alcohol helped, especially with the newest member of their group.
Of course apart from Wanda everybody else had been at least in a threesome with Natasha and Maria, and even Wanda seemed eager for them to start. Or perhaps they were all just horny for Natasha's incredible ass, not that Maria could blame them.
Along with her big boobs Natasha's fat ass really was her best feature, the ultra-tight leather pants she was wearing really showing it off, Natasha constantly finding excuses to turn around and sometimes even bend over to get her friends ready to pound her ass, just like many of them had been doing for years. Well, sort of like it, given this was going to be like nothing they'd ever experienced before.
Maria still had her misgivings about all this, especially the venue, as Natasha had been adamant about doing this in Avenger's Tower, in the exact same room The Avengers held important meetings and the occasional party.
Natasha felt it would heighten the feeling of humiliation, and there were cameras everywhere so later they could edit the footage and create their very own home movie chronicling The Black Widow at her most sexually depraved.
Maria had to admit that last part was appealing, but it was risky as the public could easily get their hands on the footage and there was a very good chance they would be interrupted by a card-carrying member of the Avengers or one of their many enemies.