Rob, all reason lost to him in his obsession and overriding desire for Mary's warm milk, turn and pounces Mary's giant udder. With a yowl Rob gulps down one teat, it slides into Rob's mouth, the flesh squeezed around his lips, but swelling back out once inside. Mary moaned in deep pleasure.
Rob's mouth squeezed the teat tightly and Rob began to move his head back and forth over the teat. The teat spurted warm milk to splash against the back of Rob's head and trickle down to settle in his feet. The taste of the milk was intoxicating and Rob's attention was solely to drink all of it up.
Mary was enjoying the milking, it was even better than before. The rubber stimulated her teat and relieved the pressure of the milk. It was wonderful.
Rob continued to pump Mary's teat, drinking more and more of the milk. The milk was filling Rob up. It reached his knees, then his hips. He felt it fill out his penis. He absently stroked the weighty appendage. Still Rob continued to drink the milk, it didn't seem to be making too much difference in Mary's udder. It was still swelled with gallons of milk.
Soon, the milk had filled Rob up to his chest and had begun to balloon his belly outward, giving him the appearance of being fat.