Suddenly it hit him harder than Mary's teeth did. He is inflatable now, and Mary is nothing but an air filled tiger balloon. He starts to take in deep breaths, filling his own tiny body and growing as he did so. Because Brett was taking in the air from Mary, she didn't notice a change in volume or height. She did notice Brett moving up to her mouth however.
Now almost a foot and a half tall, he pulled his way up the inside of Mary's body, and forced himself out of her mouth. Once free from the confines of his rubbery prison, he pushed his mousey lips firmly into Mary's. With great shock Mary could feel her body shrinking down, as Brett sucked as much air from her as fast as he could. Increasing his size whilst Mary could only watch her own dwindling. As Brett pulled away from her, Mary now found herself smaller than Brett had been before. She was no more than an inch tall now, and looked up at the giant rubber mouse with fear.
Brett was no longer paying attention to Mary however. The feeling of his inflation was borderline-orgamic. He craved the feeling of growth, and began to take deep breaths. Filling hs body at an impresive pace, He stopped only to look at Mary. With an evil grin, he closed his paw with Mary inside, to stop her inflating back to normal or bigger, an stopping his fun.