Flatmates' Big Wide Yawns

Elina comes home after a long shift to find Emma in the living room. She has also just got back from work and both girls are super tired. They sit next to each other and talk about their day and how tired they are, all the while yawning widely. The problem is each time one of the girls yawns, it sets off the other one until both girls are yawning uncontrollably their mouths stretched wide open as they do so until they both decide it's time for bed.