"Sherlock? Are you okay? You've gone pale," John raises a hand to press against Sherlock's forehead, "you're warm, are you feeling alright?"
"Excuse me a moment," Sherlock chokes, standing and dashing down the corridor from the small on board café.
John watches where he'd disappeared to for a moment before it dawns on him. He sighs and puts his half eaten packet of crisps in his coat pocket. He purchases a bottle of water from the café fridge and follows Sherlock's path.
He confidently strides into the men's loos and raps his knuckles against the door of the only occupied cubicle.
The door is wrenched open to reveal a very ill looking Sherlock, breathing heavily. His scarf is half untangled and hanging from his neck and his hair is even more unruly than in one of his worst fits of boredom.
John pushes past him and sits on the floor, slumped against the cubicle wall, and holds out the water, "thought you might want this."
Sherlock closes and locks the door, sitting opposite John and taking the water. He gulps down a mouthful and shudders, leaning heavily against the wall.
"You should have told me you get seasick. I could have bought you some tablets."
"No use," Sherlock waves his hand in dismissal, "I've tried every brand of travel medication since I was a child. None of them work."
"You could have warned me then," John shuffles himself to get comfortable, nudging his foot against Sherlock's shin, "then at least I could have been prepared for this." He waves his hand at Sherlock's general form.
Sherlock sighs loudly, "I'm fine in trains and cars, it's just boats my stomach can't handle."
"And poking around dead bodies, don't forget that one."
Sherlock smirks, taking a sip of water.
"Who would have thought? Sherlock Holmes, the man with the quicksilver tongue, feared by half of London, could be defeated by a boat and some bad weather," John chuckles.
Sherlock's eyes shoot daggers, but before he can retort he groans and clutches his stomach, making John giggle more.
"Just wait until this ferry docks, John Watson. As soon as I can move without needing to heave into the toilet, you will no longer be laughing."
John snorts and presses his hand against his face, "I'm sorry." His shoulders shake with the effort of trying not to laugh.
Sherlock groans and buries his face in his knees, suddenly appearing very young.
"How much longer are we stuck here?" Sherlock mumbles into his trousers.
John dabs at the corner of his eye, "half an hour. We're almost in Calais now."
He nods and they're quiet for a few moments. Sherlock sips at his water and tries not to focus on the gentle rocking of the ferry.
Sherlock opens his mouth to say something, but quickly snaps it shut before lurching over to the open toilet lid. John instinctively leans forward to take the water and gently touches Sherlock's shoulder.
"I knew we should have taken the Eurostar," John sighs, rubbing small circles between Sherlock's shoulder blades.