[OOC: I combined a few suggested titles into one chapter.)
The huge snake creatures lay intertwined, moaning as scaly flesh grew and bulged against flesh. Brendon's penis found Vipress' vagina, and the two started bucking, knocking over furniture and causing plaster to start falling from the ceiling. "Yesss...." moaned the Vipress, caressing her expanding breasts. Brendon's expression changed from extacy to horror. His eyes opened wide, as he felt something tugging at his insides. It felt as though he was being... drained. He writhed and hissed, and Vipress remained unaware of what was happening. There was a gurgling sound, like liquid being sucked out of a container, and Brendan started to shrink. His arms and legs were starting to reappear slowly, as though someone was pushing limbs into a latex membrane. The opposite was happening to Vipress, who was slowly reverting back to her snake form, larger than ever. She only noticed when her breasts started to recede. She looked down, her horror mixed with extacy. "No! we're changing back.... yessss, sssso good, more.... no, what'sss happening to usss?" She felt confused, and in the throes of passion was unable to focus to deal with the problem. Brendan, not experiencing much pleasure anymore, was more clear-headed. "The formula must not work on humans!" He grunted as his face changed back to that of a human. "Damn you Rick!"
A few minutes of wild bucking later they lay on the crushed remains of Brendon's bed, exhausted. The vipress was back to her snake form again, and Brendan was a human again. The difference being that Vipress had grown to a full thirty feet in length, and thick as a giant constrictor, while Brendon now had a two-foot penis. Brandon stared at the ceiling, while the Vipress lay her large head on Brendon's stomach, affectionately licking his face.
They both looked at the remaining spraybottles...