Whisper to her

"You're gorgeous, Sara" you whisper "I want you so much, please tell me that you feel the same way."

"In fact, I don't." She answers, pushing you aside and pulling her panties back on "It was fun, unexpected and quite pleasant, but now you just want to bang me like any other guy. I can't say that its impossible, but you don't want me. You want to lose your virginity, you want my body, you want to put me on a personal list of satisfied girls. "She is dressing fast while talking. Looks like she has some experience in dressing quickly. "Please, don't take it personal. You're sexy and I don't care much about the fact that you are my cousin, but to agree to that, I'll need more than instincts."

"I like you as person too." You try pleading.

"When it will be 'I like your body too.' Then we'll talk... maybe. I already allowed you quite a lot today." She answers almost fully clothed "Hey, don't be so sad. Guys like you will get laid. And sorry that I am acting like a cock-tease, but I never agreed to be your girlfriend."

"No problem" you answer and start getting clothed yourself." I can't complain, I'll remember that blowjob for months. You were great, thank you. "You are disappointed, but Sara is right, she never promised anything.

"By the way, thank you for helping with my headache, I should use human vibrators more often. Better than pills." She heads out the door. "See you later, don't expect me until later this evening." She leaves, leaving you unsatisfied and horny as hell.

And still, that little sexual adventure made you much more bold and self-confident. Now you are ready to aim for more than just some oral action.

You have several options: You may try to visit Lexi and seduce her, if you almost got a cousin, getting a stepsister may be possible. You can call one of your many female friends and try to get her to come over to your apartment. Or maybe you can prepare for Sara's return and try to change her mind.