An email from Sarah

Emily got out of the tub and was soon wrapped with a towel as Alex got to work drying off her big sister. As Alex did so Emily took the chance to grope the petite girl. No matter how much Emily played with her little sister the sounds she made when Emily played with her body turned Emily on almost as much as looking at her cock sucking lips, cum dump ass and body made for futa dick.

Emily reached down and squeezed Alex's ass eliciting a moan and a thrust back so Alex could get as much of her ass groped as possible. The sight of her little buttslut of a sister acting like that hardened Emily's cock. The sudden thud Alex felt as her big sisters cock hardened and jabbed into her cock made the small girls legs weak as the desire to swallow something filled her head.

Emily considered dumping a load into her little sister right now to make sure her lower half was still working but there was a rather big problem waiting. Sooner or later Sarah was going to remember what had happened and that knowledge was going to eat at Emily.

Once she was dry Emily patted Alex for being a good girl. She wrapped herself in a fresh towel and walked out of the bathroom, leaving Alex a little flustered after not getting the dicking she was expecting. Emily walked into the living room and turned her laptop on.

She was immediately greeted by an unread email from Sarah. Emily tried to swallow the lump in her throat. She opened the email trying to think of her to get herself and the marker close enough to Sarah and whoever Sarah may have told to fix all this. Emily started to read.

"Hello cuck."

Emily let out a sigh of relief, if that was her opening it was likely she hadn't cleaned off the mark just yet. Emily read on.

"Are the show you got to see I am sure you want to do it again sometime."

Emily rolled her eyes, Sarah really got off on the whole cuckquean thing.

"But that isn't going to happen."

Emily felt the panic rise again.

"Nor are you ever going to fuck me with that stupidly big cock."

Emily felt a grin at the compliment before the reality of what it meant hit her. The mark was gone Sarah remembered.

"So here is what is going to happen. You and your sis are going to complete the Sorority's tasks, get into Omega Pi Sigma and you are going to be my protege."

Emily was feeling kinda lost right now.

"And if you don't everyone on campus will know about futa who fucks her little sister."

Emily gulped as she tried to think of a way out of this, the marker could still save her but getting close and alone might be harder than she thought.

"Now if you accept send me a picture of your cock buried in your little sisters throat."

The email was finished and so was Emily. She was freaking out. Sarah didn't have proof that Emily had a cock but she was the president of the sorority and who knows what she could do to Emily and Alex, maybe even get them thrown out of uni altogether.

As Emily panicked Alex, feeling a compulsion to help her big sister walked over and started to stroke Emily's hair in as soothing manner as she could. The petting did actually help Emily who took a breath and thought about her options. She could do nothing and hope that Sarah doesn't do what she threatened. Or she could send the picture and give Sarah actual evidence, at least evidence of Alex sucking a cock. But maybe there is a third option she hasn't seen yet.