Bloody nose bleed incident

Just as we were returning home from supper last night, Clarissa and I were having a few laughs with her younger sister. Christa in the back row seats of the car.
Suddenly Clarissa's head darted diagonally backwards while Christa too was busy chuckling. Her head struck Christa's nose and lips. Soon afterward laughter turned into cries in pain and blood flowed from her left nares and mouth.
Now it really looked like a scene from a WWF fight gone awry. Mommy thought Clarissa did it on purpose but luckily I was a witness to the incident. Since when did girls play rough? Or did they do that all the time when we weren't watching?
I quickily applied pressure to the bleeding nose and split lip for a few minutes and stopped the bleed. She was lucky to get away with nothing which required suturing at the clinic. Thank God!