It should be "yourselves".
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
ReegisChildren, behave yourself in the theatre.And it looks suspicious to me... Is 'yourself' justified somehowGPY is of course right on the grammar point, but I don't find it egregiously wrong; it is certainly common enough in real conversation: the teacher is addressing herself to each child, so it is stronger in the singular.