With your brother

You stared at her in shock. "You're...you're kidding, right? You've got to be kidding."

Amy shook her head. "I want to fuck your brother, and I want you to watch." She squeezed your crotch, and you gasped as your cock strained against the fabric.

"But why him?" Out of all the possible names she could have said, you really weren't expecting her ideal bull to be your own brother Alex. You knew girls often found him attractive, but as far as you could remember Amy had never expressed any interest in him for the five years you had been together. Not in front of you, anyway.

"It's not because I don't love you, or I think he's better than you, or anything like that, okay?" Amy kissed your cheek to reassure you that she didn't want to end your relationship. "I just really want to cuck you with someone you know, and Alex is cute." She kissed you again. "I love you, John."

"Why someone I know?" You struggled to work out why she would want to do something so depraved.

"To see if it's a major problem. If you can watch me getting fucked by your brother, or someone else you know, and we still stay together, then our relationship can take anything."

"So why do you want to cuck me at all?" Despite her words, you felt upset and humiliated knowing that your sex life was so inadequate that Amy wanted to fuck other guys. It wasn't like you'd never made her do any kinky stuff, but nothing on this level.

She squeezed your crotch again. You were painfully hard now. Amy leaned down to plant a love bite on the side of your neck as she continued palming you through your jeans. You realised you were getting close to cumming despite the situation. Christ, was the idea actually turning you on? You shivered as Amy pressed her lips against your ear and whispered to you.

"Because it would be hot."

Amy's words pushed you over the edge. Your entire body shuddered as you came in your pants. Amy stopped touching you, and looked into your eyes.

"John, I know this is a hard decision for you to make, but it really turns me on to think about it. I'd really enjoy doing it. I think we both would, judging by how hard you just came."

You sat there in silence for a minute as you gathered your thoughts after that amazing orgasm. You still had to deal with the humiliating fact of your girlfriend wanting to fuck Alex in front of you, but at the same time the idea turned you on just a little. Amy kissed your cheek again and handed you her phone.

"Call Alex, baby."