Ugokukara nurinikui (動くから塗りにくい) is a Japanese expression meaning "it's hard to color it, if it moves", and it's a tag that became popular on Twitter in 2015. You start with a character lineart in black and white, and draw many different version of the same character, together with its reaction to being colored! Depending on the character, they might hate it, dislike it or love it... It really seems like you're having a personal interaction with the character on the other side of the screen!
Today we collected a number of illustrations tagged ugokukara nurikinui. Enjoy!