Solve For The Variable XXX

She helps him out by making him feel a little more comfortable while he masturbates on the couch. She plays with her pussy and watches him stroke his long ruler. Then he adds his cock to her pussy, and the good times grow exponentially. He sticks his long inequality inside her and works through all the calculations with ease. She loves every inch and rides him up and down, showing him all the possible values that a variable can have. Finally, she takes his derivative on her chin and is totally satisfied. This seems like how math should always be taught, doesnt it?