He had to get out of there. Anywhere would do. Mycroft pushed his way through the people, ignoring the exclamations from them. He had no idea why his parents had decided to have this gathering. They'd known he wouldn't like it, but they'd gone ahead anyway. Mycroft felt the curly fur of his little brother's red setter, Redbeard, against his leg. He kicked his foot out at the dog, and felt him move away. Mycroft carried on striding through the crowd, until he got to the hallway. He caught a glimpse of Sherlock. That was the last thing he needed! He kept his eyes fixed ahead of him. He could barely hear Sherlock's remarks through his whirring mind. When he managed to get to his room, he laid on his bed, his hand dangling over the side. Mycroft could feel the rapid rate of his heart and his breathing. Suddenly, he felt silky fur underneath his hand. After hesitating, Mycroft combed his fingers through it. Redbeard jumped up onto the bed next to him. Without hesitation, Mycroft wrapped his arm around the dog, still brushing his fingers through his red fur, and tried to calm himself down, to steady his breathing. Once he'd steadied his breathing, Mycroft buried his face in Redbeard's fur. He was surprised that his comfort had come in the form of his little brother's dog, but he wasn't going to fight against his only source of remedy.
A/N:
Sorry this is so short! I just had to write something for my deadly serious headcanon; that Mycroft has severe claustrophobia. IDEK! I think the idea came from drama-ing up another piece of work I write, and it kind of went downhill for my favourite character ever since.
~Ellis~