Kirsty deserves it

I decided Kirsty's 'lesson' would be best served by finishing with me cumming inside her rather than her sister. She'd 'learned' so much already that it seemed a shame not to top it off letting her experience my climax.

I withdrew causing Sydney to stop eating out her sister to look back at me. "What are you doing?" she asked "I was so close."

"Sorry" I said "but we are here to teach Kirsty about sex and I think it's only fair that she gets to experience what it feels like when a man climaxes inside her. You already know what that feels like".

"That's O.k." she said "I want Kirsty to enjoy herself as much as possible and I think she'll love the feeling of your hot cum squirting inside her."

"W-W-What's happening?" asked Kirsty as Sydney stands up and moves around the bed.

"John thinks that in order to really understand sex you need to know what it's like to have a man finish inside you." said Sydney "and I agree. While he is showing you what that feels like you can show me what you've learned about cunnilingus. Now slide down the bed so your butt is down at the end."

Kirsty did as instructed while looking somewhat dazed. Her pussy was soaking from both her own juices and her sister's mouth, and was showing signs of urgent arousal.

Once she had positioned herself correctly Sydney got up onto the bed, placed her legs on either side of her sister's face and lowered her pussy toward Kirsty's mouth. Kirsty leaned her head forward and began to tentatively lick. Her nose scrunched up cutely as she was obviously still a bit squeamish about licking pussy but she quickly seemed to decide that if her sister could do it, and make her feel so good by doing so, she could do the same in return. She put her hands around her sister's thighs, pushed her face in and began to lap away causing Sydney to groan "Yes! Yes! Good! Just-Just like that! God girl! Goood!"

Once I was sure Sydney was happy with Kirsty's progress (and was quickly on her way to the climax I had refused her) I positioned myself between Kirsty's legs, placed my cock-head at her opening and then slowly slid inside her. She, of course, stopped, much to her sister's consternation, but, once over the initial excitement remembered what she was doing and returned her attention to her sister's cunt.

Despite her hot, soaking, tightness I found that I could hold back my orgasm with little effort and so I continued thrusting inside her until I saw on Sydney's face that she was about to climax herself. As she cried out and came all over Kirsty's face I thrust deep inside Kirsty's pussy and pumped my load into her allowing her to simultaneously experience both the end result of bringing a woman and a man to climax. Kirsty must have somehow been holding her own orgasm back so she could finish with me because as I sprayed my cum into her I felt the waves her own climax convulse through her and heard her cries of ecstasy (muffled somewhat by her sister's pussy).

Despite having cum harder than I ever remembered doing before I knew I could continue if I wanted to, however both girls looked drained.