When a person has so much luggage that they have to carry backpacks on the back as well as on the front. Wrapping all their luggage around themselves like the shell of a turtle.
When a man orgasms on a female's back, then gets her to fall asleep on her back. While asleep, the semen adheres to the woman's back and to the bed, such that when she awakens and attempts to get up, she is unable, which leaves her to flail her arms and legs like an overturned turtle.