Beth is discovered.

Becky is lost in the sexual energy, moaning to the attention of her invisible sister, Beth. You decide it's now time to reveal her. "Mmm... ah... AHH!" Becky lets out a surprised yelp and quickly gets to her feet. "Beth! What are you doing in here?!" she cries in complete astonishment.

"Oh my god! I'm so sorry, Becky! I didn't mean to be in here while you were... I mean, I was in here trying on your clothes and... I didn't know you were coming home so soon and... I didn't mean to stay... You guys came while I was undressed, I didn't want to be caught like this... I..." Beth rambled on trying to unravel all her thoughts at once. "I'm soooo sorry, I'll leave you two alone!"

Beth tries to rush out the door, but it is still locked. She looks around frantically for another way out. She looks to the window.

"Probably not a good idea," Becky's friend chimes in, "What would the neighbors think with you going out like that?" She gives Beth a playful smile then turns to Becky. "Your sister's a hottie."

Beth turns back towards her sister, "Beck, I promise I won't tell mom and dad, just let me out and we can pretend I was never here..."

"...You sure you want out?" Becky asks after a seemingly long pause. Beth nods silently. "Well, I'll let you out if you do one thing for me."

"Anything," Beth agrees.

Becky sits down on the edge of her bed and spreads her naked legs. "Finish what you started," she orders with a smile.

Beth hesitates for a moment, not sure what to do. She looks Becky in the eyes and sees that her offer is serious. She then looks over her sister's nude body in all its splendor. She slowly goes down to her knees and leans towards her sister's open legs. She sinks he head into the awaiting cunt and with slight hesitation, stick out her tongue. She gives the pussy a quick lick which exerts a deep moan from her sister. This encourages her to explore further. She delivers a more liberal lick on the mound, followed by a quick, exploratory tongue inside the pussy. Becky stops her at this point and pulls her back.