Wiktionary
colour up
alt. (alternative form of color up English) vb. (alternative form of color up English)
Usage examples of "colour up".
You can colour up till you're prawn while I go squirt with any cockle.
Von Ziegler, he noticed, had a lovely black eye which was beginning to colour up, and his white collar had been torn away from its stud where somebody had grabbed him at the back of the neck.