Play her own younger sister

"Nobody would believe I'm a little kid." said Lauren, ashamed of even considering this ridiculous option.

"Oh, I'm sure if you wash off all that adult make-up and let me help with your hair, you could be a pretty convincing child." she sneered. "My 'little' sister."

Lauren just glared daggers at her sister. Would it even work? Could it?

"I would hurry if I were you. They'll be here soon."

Despite not being convinced yet, she bolted towards the showers. She used one of the open ones to scrub away all the make-up she had put on earlier that day. It wasn't as effective as with her proper tools in her own bathroom, but it was the best she could do at the moment.

When she returned, Vanessa greeted her with a wide smile. She was happy with the outcome. Without make-up, Lauren definitely looked younger. Though not everywhere, but they DID have similar features, so she knew something like this would happen.

"Sit down, I'll do your hair." she motioned to the towel.

"What are you going to do with it?" asked Lauren, feeling uneasy. "Don't you dare cut it."

"Nah, I'm just giving it a younger-looking style." she chukled.

Lauren sat down on the towel between her sister's legs and felt her fumbling with her hair for a while.

"Done." said Vanessa, "look at yourself, 'little' sister." she held up a handmirror towards Lauren.

Lauren immediately stood up and turned around. Her reflection came as a mild shock to her. She could see those small freckles on her nose she had always hated and desperately tried to cover; and her hair was in two pigtails with a little pink flower around each, giving her an adolescent look. She looked like a 12 year old. Or younger.

"Oh my god, what have you done?" she yelled as she stepped back a few feet in disbelief.

"You said 'nobody would believe you are a kid' before. Well, now nobody would believe you are an adult woman." Vanessa smirked. Her handywork turned out better than even she would have expected.

Lauren turned crimson at that comment, mostly because it was true. She had always been younger-looking and hated it. Now she looked like... like a little kid... Her womanhood had been stolen away from her.

"Do you think it's enough to deceive Tony?" asked Vanessa.

"It... yes..." she admitted. She would have had a hard time getting a drink in a bar, let alone trying to convince her boyfriend that she was the sexy lady he had been courting. She could feel her stomach turn at the mere thought of it. But it was better than revealing her secrets. Was it?

"I'll call you Jessica, my little sister." snickered Vanessa. "Now, off with the suit and get into character."

"What?"

"Oh, come on. How old do you think you look now? Did you really expect to wear that swimwear?"

"I - I didn't even want to wear it! You wanted me to!" she argued.

"I wanted my 'older' sister to wear a sexy mature suit for the beach. I want my younger sister to not dress like a slut. And I only see my younger sister."

"I - I... What am I supposed to wear?" asked Lauren, her eyes starting to fill with tears.

"Don't worry about it. I have just the thing for you." she patted her bag. "Now, off with that slutty suit. You are way too young for that."

"I... I can't."

"Well, it is going to be an awkward conversation between you and Tony then." shrugged Vanessa as she leaned back on her towel. She knew she had Lauren where she wanted her to be. All she needed was a little push.

With a heavy groan, Lauren wiggled herself out of the suit and it landed around her ankles. She was naked on a public beach. Bare-ass naked. With people around.

Vanessa picked up the suit with a satisfied smirk. She put it in her bag then leaned back to take in Lauren in all her glory. Her handywork. The sight was better than she had expected. Her older sister was gone. In her place stood a squirming, shapeless, pale and very naked little girl with adorable pigtails, surrendering to her 'elder'. Her 'little' sister, Jessica.