yawnversation
A yawn performed when you are talking to someone who tries to conceal their fatigue by yawning with their mouth closed. Akward facial contortions are a dead give-away to a yawnversation.
Non-yawner: "...so i said, fine, i'll work your shift, but she's all like, no forget it..."
Yawnversation-er:(silence accompanied by eye squinting, scowling and the jutting out of the chin)  