Sherlock: *whining*
John: Don’t you be like that. If you are opposed to transmutation, you should not have let a demon flatshare with you. You’ll be back to your normal, irritating self in an hour.
Demon!John changes Sherlock’s shape to aid them in a case that involves Underworlders. Sherlock never approved, and resorts to pouting at John while he waits for it to wear off afterwards.