Benjamin's thoughts froze. He was completely taken by surprise and couldn't react for a long time. Then, his first sensation was the strong taste of what he guessed was the flavor of alcohol. He could only guess since he had never drank any before, after all. His rationality came back a short while later and he pushed Grace's head away in reflex.

"Hehe, your lips are warm, Ben."

Grace was still out of it, licking her lips as if she had tasted something delicious. The current situation confused Benjamin a lot. He looked at his sister's expression and could see desire and a wish to monopolize him. This triggered his memories. Grace was five years older than him and so, by the time he became a hormonal teenager, she was already a full-fledged woman, with curves in all the right places. As a young woman so close to him every day, she obviously came to be the target of his fantasies and he couldn't remember how many times he masturbated to her, imagining doing this and that to her. What was worse was that she was always doting on him, not minding close physical contact. On his side, he sometimes managed to catch glimpses of her body when she changed clothes without remembering to close her door. One time, when he was at the height of his horniness, he even went to spy on her taking a bath, and the image of her beautiful naked body remained in his brain to this day.

That same sister was now looking at him the same way he had been looking at her in the past. He didn't manage to suppress a feeling of excitation, his penis hardening at the situation. Even drunk, the bump in his pants didn't escape Grace's eyes and she grinned lustily.

"Did my kiss make you hard, Ben? Hehe, don't worry, your big sister will take care of everything."

She unzipped his fly before he could react, took his dick out, and observed it. It was good that there were no other passengers on the train car, even though it was not sure if Grace would have cared much in her current state.

"You're so big, Ben."

The person in question, on the other hand, was feeling very conflicted. Contrary to the thing he did with Chloe, which was for education purposes and where they didn't even touch each, this was a much more serious issue. He knew that he should put a stop to the whole thing but was also incredibly exhilarated by the situation. It was his sister, his family member! The same sister that he had spent most of his teenage years fantasying about. But still, they were related by blood!

His complicated thoughts came to a stop when Grace suddenly gobbed his penis whole, enveloping it in her warm and wet mouth.

"Ah...! Grace..."

She looked at him while sucking on his cock, happy that he called her name in his pleasure. However, Benjamin quickly felt, after the initial surprise, that she was quite clumsy in her blowjob. Remembering that Jolene and Kamryn said that all three of them had no experience, it made sense, and even more when considering that she was drunk.

Seeing the sister he had venerated in his fantasies sucking on his cock so deliciously finally broke the last layers of resistance inside him. He decided to not care about anything anymore, and come what may.

Luckily, Benjamin's head was still on her lap, in a strategic position. He extended his legs, lying down completely, using the whole row of seats for himself, and tapped on Grace's thighs.

"Grace, let my head down and get on all four."

She looked at him and slowly obeyed his words. Benjamin's head was now on the last seat of the row and Grace was above him, in a classic 69 position. Benjamin lifted her dress, removed her panties, and made her drop her waist until her pussy was right on top of his mouth. it had a patch of hair above her vulva and was already very wet, her juices glistening on her labia. Then, without hesitation, he started to eat his sister's cunt, making her let a long moan out in his cock and stop her blowjob. She tasted fantastic, just like in his fantasies, her abundant sweet juices entering his mouth, fulfilling him. He started to lick her pussy over its entire length, causing her to shiver and take his penis out of her mouth.

"Ah, Ben... Your tongue feels so good. I always dreamed of a situation like this. Ah... I love you, Ben! I love you so much! Don't stop!"

No one hated receiving such an ardent confession of love and Benjamin was the same. At her command, he continued his efforts, now inserting his tongue in her hole while slurping her juices. She panted hard at the stimulation, her blowjob now completely forgotten. Benjamin didn't mind, though, and switched to her clitoris, sometimes licking it, sometimes sucking on it, sometimes flicking his tongue over it. That became too much for her and sparked her orgasm, as she twitched violently, shouting her pleasure and letting out plenty of juices on his face.

"Aahh! My little brother's tongue is making me come! Aaaahhhh!"

Benjamin had just brought his big sister to climax, the same sister he had always admired and had fantasies on. This gave him a kind of incredulous feeling, as if he still had trouble believing it really happened. That also soon transformed itself into euphoria, making his dick twitch in excitation. Grace had just had the time to come back from her peak to witness it, realizing that she had focused on her pleasure too much.

"Sorry, Ben! I will take care of you!"

She resumed her fellatio, pumping her head over his dick as if to make up for her blunder. A few seconds later, Benjamin also restarted his cunnilingus. This time, he directly focused on her clitoris, her best spot, while sending two fingers into her pussy. The double stimulation was too much for Grace and she whimpered, stopping her blowjob once more. She closed her eyes, focusing on her twat's sensations, until she climaxed a few minutes later, her pussy squeezing his fingers and her body trembling like a leaf. Then, she noticed that she had forgotten about her work once more and drilled her head up and down on his penis.

Benjamin thought the situation was funny and he repeated it several times, Grace getting more and more unfocused due to her repeated orgasms, while also more and more desperate during the brief period she resumed fellating him. Finally, it was too much even for him and he announced.

"I'm going to come, Grace!"

Her eyes widened in anticipation and she sped up her head movement. Benjamin's waist quivered and he came grandly, all his pent-up feelings exploding in one go, sending waves after waves of cum in her mouth. It felt incredible to ejaculate in his sister's mouth and his sperm just wouldn't stop coming out. Grace bravely accepted everything, gulping all of his semen until nothing was left. When she felt that he was done, she suddenly relaxed, her head and body dropping on him. Benjamin extracted his head from her cunt and looked at his sister, who was now unmoving. He soon realized that she had fallen asleep, probably due to the combined effect of the alcohol and her sexual exhaustion, her head still in his crotch and his penis still in her mouth.