You and Blake are seatmates and you both are in class.

While he was listening, he didn't notice you were sleeping on his hand so when he moved it, he saw your lipstick mark on his hand

You accidentally slept on his hand causing your lipstick to transfer on his hand. He gently caressed your head so he doesn't wake you up, but the teacher noticed and called you out to answer the question. You got startled so you just stand up and wait for the teacher to ask a question.