Saturday morning, and Gretchen slept in. About 10:00 Petra called her and said she would pick her up at 11:00. Gretchen asked what they were going to do, but Petra just laughed and told her that it would spoil the fun if she knew. Gretchen stayed naked until Petra called again saying she was right outside the building. Gretchen pulled on her underwear, jeans shorts, and a tank top, stepped into some sandals and bounded down to Petra's car.
"So what are we doing?" Gretchen asked as they pulled out.
"I thought a day at the beach would be good."
"Wait, I didn't bring a suit. Oh, we're not going to some nudist place are we?"
"No," Petra laughed, "then I'd have to get undressed too, and this is your kink not mine. Besides, you want to be naked where you're not supposed to be, right? I have a suit for you, don't worry."
"Hey, don't take that kink comment the wrong way, okay?" Petra continued after a bit of silience. "We all have our own kinks, and that's what makes us interesting. This one is yours and that's cool. It's just not mine."
"So what is yours? You never talk about yourself," Gretchen asked.
"Maybe if you make it to day ten I'll let you know."
They got on the highway to head to the beaches, and Petra pulled over on the shoulder. She reached back and pulled a bag in to the front seat. She handed Gretchen a white two piece swim suit, and told her that she should put it on. Changing clothes in a car along the Interstate seemed pretty tame to Gretchen now, so she peeled down her shorts and panties, pulled on bikini bottoms, removed her bra and top, and with a giggle, put on the bikini top. The bottoms were actually not too radical, sort of a Brazilian type cut. The top was strapless, but covered her fairly well. The fabric seemed very thin however, and neither top nor bottom were lined. Her nipples showed as prominent bumps in the top, and with no hair down there the crevice of her vulva was easy to spot. Her tan lines did not match the bikini bottoms, and the white skin around the fabric just made it seem more revealing.
"Fits me I guess," Gretchen commented, "but it doesn't really hide very much. Where did you get it?"
"Amazing what you can find on the internet. Now here's the deal. You're wearing nothing more than that bikini until I drop you back at your place. The drive out there, on the beach, off the beach, all the way home. Got it?"
"Wow. You've put a lot of thought into this stuff," Gretchen said with a grin.
"Hey, what are friends for?"
Petra pulled out onto the highway, and they drove the better part of an hour to the state park. The park consisted of a bunch of dunes along one of the Great Lakes, with some decent beaches. It wasn't Waikiki or South Beach or anything, but on a summer day in the Midwest, it was a nice relief from the heat and humidity. Petra paid the entrance fee, and found a spot to park. As they walked to the beach it started to sink in to Gretchen about how hard this would be. Petra had a gray tank dress over her swimsuit, and carried a beach bag with their stuff. Everyone else around her was wearing shorts and T-shirts or some kind of cover up. She was the only one walking around in a bikini, and one that didn't hide that much. Guys were checking her out constantly, and girls were giving her dirty looks that said "Slut!"
It got better on the beach, just because now other girls were in their bikinis, although guys were still looking at her a lot. They walked for a while until the crowds thinned out, and Petra picked out a spot. They spread out their towels and sat facing the lake, watching the waves come in. Petra peeled off her cover-up, revealing a black bikini that Gretchen had to admit made her friend look pretty good. It wasn't as revealing as Gretchen's, but she was sure guys would be checking out both of them. Petra put sunscreen on herself, and handed some to Gretchen.
"Let me get your back," Petra suggested as Gretchen finished up her front. Gretchen laid down on her stomach and Petra squirted a bunch of lotion on her back and down her legs. Petra rubbed it all over her back, and then undid the top to make sure she got under it. Then she did the backs of Gretchen's legs, working her way up to her butt. Gretchen had to admit that it felt really good. Laying in the warm sun, the feel of hands rubbing lotion in, it was delicious. As Petra's hands got closer to her butt, she wondered what her friend would do. She knew it would be weird, but she was hoping that Petra would rub the lotion on her rear, it all just felt so good.
Petra did not disappoint her. She worked her hands up to Gretchen's ass, and then focused in on rubbing the lotion into her cheeks. She even pulled the suit up into kind of a wedgie to expose most of her friend's rear end.
"Leave your suit bottoms like that, it will give you a good tan." Petra laid down next to her. Gretchen re-tied her top, kneeled by her friend and returned the favor. She put lotion on her hands and started rubbing it into Petra's back and shoulders. Petra had wonderful olive skin, and her body was trim, if not as athletic as Gretchen's. Gretchen wondered to herself why Petra didn't dress more to impress. She certainly looked great in a swimsuit. Gretchen undid Petra's top to get lotion all over her back. She thought briefly about pulling her friend's top off, but remember the comment about exhibitionism being Gretchen's kink not Petra's, she thought better of it. When she was done with the back, she started working up Petra's legs, rubbing them a little longer than was strictly necessary, but she wanted Petra to feel a good as she did. She got up to Petra's rear, and she realized her heart was racing. She put more lotion on her hands and began rubbing, working her hands up under Petra's suit. She pulled Petra's suit up to make it more of a thong, and noticed that no tan lines appeared. "Hmmm," she thought to herself, "an unexpected side to Petra."
Petra reached back and pulled her suit in place, but she had a wide smile on her face as she thanked Gretchen, saying it felt really good. Gretchen laid on her back to soak up some rays. Petra leaned over and told her to spread her legs some, to give people walking by a good show.
"Wider. A little wider. Good" Gretchen's feet were now almost three feet apart, and she was sure that someone walking by would know for sure that she was shaved down there. The feeling of being exposed was making the pressure build up inside her. She propped herself up a bit on her elbows, and watched the lake and the occasional person walk by. She was definitely attracting attention from the guys who passed by. Most of them tried to look like they weren't staring, but some of them openly gawked. The whole thing turned Gretchen on immensely, and it was all she could do to not play with herself.
They girls flipped over after a while, and soaked up more sun. Soon they were both roasting hot, so they decided to go in the lake. In the only really acceptable way to get into a cold lake on a hot day, they ran down into the waves and dove under.