Pepper had been asked to work late that day and she found herself getting home at midnight, trying to be silent so as to avoid wake a sleeping Tony. The woman left her purse on the coat rack by the door and lurked through the house without turning any lights on.
She sat in a plush white chair and felt herself relaxing for the first time that day, and that was when she heard some song that sounded like Ke$ha floating in through the house. She stood up and strode over towards the source of the noise. It was coming from a stereo in Tony Stark's room. Pepper hesitated. She felt that it would be best if she knocked before entering the room, but the music was too loud for him to hear(and if she knocked he'd have time to come up with a plausible explanation for the ridiculous music he was blasting), so she didn't.
When she opened the door, Ke$ha's "Blah Blah Blah" almost knocked her off her feet, but slightly more shocking were the people currently occupying the room. Every single one of the male Avengers were standing in the middle of the room, stripped down to their underwear, and dancing. Tony and Clint had both strapped on one of Pepper's lacy red bras each and were shimmying in the middle of the group.
The respectable business woman's jaw dropped, and she didn't stop the door from slamming shut behind her. At the sound, all the mostly nude partiers' necks snapped over to look at her where she stood. After a moment of thunderous silence Pepper spotted Natasha Romanov, also in her underwear, duct taped to a chair facing the men with a gag in her mouth.
"What is going on here?" she demanded. Tony walked around his fellow male Avengers to where Pepper was standing.
"Pepper…today…we are celebrating a very special day…the day Natasha was born. This," he gestured at the mostly naked men who weren't dancing anymore, "was her one wish and we decided that such a special woman deserved a great birthday party."
Pepper glanced at Miss. Romanov, then back at Tony.
"Why did you restrain her to a chair?"
"She's into S&M stuff. Not really my thing, but like I said, anything for Natasha, our favorite lady Avenger."
Natasha squealed and struggled to free herself from her bonds.
"She doesn't look as if she's enjoying herself."
Tony nodded, with his classic matter-of-fact look, which contrasted dramatically with the given situation.
"Yeah, well, with so many hot guys in their underwear in one room, it's normal to get a little overwhelmed."
"And not only are you in your underwear, but you're also in my underwear?"
Natasha managed to spit out the bandana tied around her mouth.
"Help Pepper! They do this ever first Tuesday of the month! It's an Avengers thing. If you say no they tie you to a chair and make you watch!"
Pepper looked around at the Avengers who weren't bound an gagged.
"You people have managed to prove to me, again, that you are all psychos, congratulations." The woman began walking over to where Natasha was sitting.
"No Pepper! Call the police! Run before they get you too!" the Russian spy shrieked. Pepper turned around as she was snatched by Thor. When she struggled it was like she was trying to pull a truck with her eyelids.
Fifteen minutes later, both Natasha and Pepper were sitting on chairs, tapped down with duct tape and wearing nothing but their underwear.
"Well, this isn't all that bad," Pepper suggested. Miss. Romanov groaned.
"You haven't been sitting here for the last three and a half hours."
"Three hours?" Pepper gasped. Natasha's head flopped down and she closed her eyes in defeat.
"You could've called the fucking police."