They make a trade

The Doctor and Yaz approached the only stall they could see that looked like it sold clothes. The stall was operated by a shifty-looking green-skinned alien with yellow eyes. The Doctor did the talking.

"Hi there, do you have any, umm, bras?" The Doctor asked.

"Bras?"

"Yeah, bras. You know, the things that hold down your breasts?" The Doctor motioned to her own bra.

"Oh yeah, we got those. You got money?"

The Doctor frowned. "Crap. I didn't think about that. Do you do credit?"

"Nope. You're lucky though. I'm willing to do a trade."

"What... what do you want?"

"Your friend's undies."

"What!?" Yaz exclaimed. "You're not taking these!"

"Look, what about mine instead," the Doctor suggested, pointing towards her yellow boxer briefs with their blue stripes.

"I want women's underwear, not... those." The alien said dismissively.

"Rude. These are women's undies, I'll have you know. Look Yaz, if you give him yours I'll give you mine."

"I can't let you do that," Yaz responded.

"It's okay, I'll be fine." The Doctor slowly pulled her boxers briefs down and off, revealing her large bush. Yaz averted her eyes, before quickly removing her briefs. She took the boxers and pulled them on.

"There you go..." Yaz muttered, as she handed her briefs to the alien. He took them from her before stepping behind the curtain. Moments later he returned, a plain black bra in hand. Yaz took it and hurriedly put it on.

"You okay?" The Doctor asked.

"I'm alright. It fits well enough. Are.. are you okay?"

"Sure. Let's see if we can get to the front."

The Doctor and Yaz walked away stall, not noticing the alien staring at the Doctor's bare cheeks as they left.