Downfall/Take her thigh between your legs
From Create Your Own Story
You climb into the cab, stretching your right leg over and lowering it next to your mum's right leg, quickly followed by the left leg, which place it between Julianne's legs. During the process, you tumble backwards and fear for a moment you might fall against your mum, but Julianne anticipated this and supports you with her hands on your back. You sigh when you finally got seated; you don't even care that you sit on the hem of your dress. Julianne passes you the belt buckle. You pull the seat belt around you and lock it. The belt is cutting into your boobs; you squirm around until you can adjust it into a position that isn't uncomfortable. The squirming lets crumples the skirt of your dress even more, but before you can adjust it, the driver accelerates the car. You are pushed back and involuntary clamp your legs together.
The seat belt presses you tightly against her chest. You can feel her breasts against your back. To find a comfortable position, your mum puts her arms around your waist. You put your right hand above hers; where do you place your left hand?
