Pain in her groin

Emily woke up to an unbelievable ache. She opened her eyes and looked down to see she was both still hard and still inside Alex.

With a groan of pain she pulled out of her sister and looked down. She had almost been expecting to see her dick was falling off. It was still there and looked harder than she had ever seen.

"You ok sis?" Alex asked rolling over. As she did her hand grazed Emily's cock sending a burst of pleasure and ache through her.

What the fuck was happening. It felt like she hadn't peed in a month. "Something's wrong?" Emily groaned out as Alex's hand again accidentally brushed her cock.

"No it's not." Alex said as she sat up looking at Emily's cock. She sounded really tired. "You see if you edge for too long your spermatic cord can get agitated and tell the body it really needs to cum." She reached down and ran a finger gently over Emily's mons. It felt both good and a little painfully.

"B-but I haven't edged." Emily complained as the need the cum was driving her nuts.

"No but you have had your cock inside your baby sister's pussy for several hours who would regularly rock her hips to keep you nice and hard and ready to cum all night -Yawn- long." Alex whispered into Emily's ear as he finger ran from her mons up the back of her cock the doing small circles around her crown.

"FU-fuck." Emily moan feeling like she was about to explode. "Why?" Emily pleaded.

"Two reasons. One this is going to blow your mind." As she said that she shot down and wrapped her lips around Emily's crown and swirled her tongue sucking soft.

"OH FUCCCK!" Emily shouted. Unable to resist she grabbed the back of her sister's head and shoved it down. Feeling Alex's throat around her crown she kept trying to harder. **** to unload as deep into the warm wet hole as she could. Then she felt Alex start to swallow.

She wasn't going to last long and the she felt Alex slip a finger down and push inside her own pussy.

That pushed her over the edge. Alex was one hundred percent correct it felt so insanely fucking amazing that Emily was pretty sure she passed out for a bit. Now that she was coming too and still pumping cum directly down her throat and into her stomach. Emily let go and Alex pulled back but kept crown in her mouth so she could get the full taste of an hours long edged orgasm.

At some point Emily stopped cumming but she still kept feeling pulses of pleasure. Now empty of cum, possibly for the rest of her life, Alex let the cock go and crawled up to Emily. She moved to kiss and Emily instinctively opened her mouth. As she did she felt the salty taste of her cum push inside along with Alex's tongue.

It wasn't that bad a taste and she was hardly in a condition to resist so she just lay there being fed her own cum by her sister.

After a long make out Alex broke the kiss. "And second I wanted a nice big protein shake when I woke up and we didn't have anything in the kitchen." She planted another kiss on Emily's lips. "Thanks for that big sis." She patted her stomach with a greedy grin on her face.

"What the fuck sis!" Emily asked as she recovered enough. "That fucking hurt."

"Then next time you want to prove you own me after some stupid domme makes you doubt it don't treat me like a onahole without asking first."

"I thought - " Emily was terrifed she'd fucked up.

Alex kissed her again. "I'm fine sis." She got out of bed and stretched bending to show her curves. "Nothing would ever break us up, this was just some ****. Also next time you want to prove you own me I could do a firmer hand." She wiggled her ass for emphasis.

"Did not think," Emily thought about the sister mark she had put on Alex, "I would want a brat of a sister." She crawled over to Alex and stood up behind her. She was taller and wrapped her arms around reaching down to run a finger around Alex's clit.

"Maybe you just like rough sex and wanted someone to encourage you to have some." Alex grinned pushing her ass back wedging Emily's cock between her cheeks.

She had a point. Emily and Alex had had a lot of rougher than exactly vanilla sex since they started. "Maybe." Emily said pushing her hips forward. To her own surprise she did not get hard between Alex's cheeks. "But I think for now you have drained enough."

"Tell me about it." Alex faked a burp, stroking her stomach as she pushed it out. Admittedly the idea that Emily could fill her with enough cum to make that fake bulge real was a thought she was going to be pumping later but she was actually spent.