I imagine they would get up to a great many shenanigans
"Sherlock! Must you experiment on Gladstone! Poor boy’s croaking colours for weeks now!"
Waterclour done for my good pal Binta's Birthday this past weekend!
PotterLock in the form of a homoerotic Sherlock watercolour could never be enough of a testament to her greatness
(Anyone who thinks John isn’t a Hufflepuff can go home)