Adam still has doubts, but simply cannot deny Sarah's superior futanari cock

Adam's eyes went wide open at that suggestion, a look of surprise on his face. He had never taken anything up his ass. He didn't tick that way.

There was a distant and feint voice in Adam's mind, that this was all wrong. Especially now, when he finally had the big cock that he had always dreamed of. The voice told him that Adam was supposed to be the one in charge. That he was the one who should do the fucking. That he could easily use the strength and power of his new body to make his sister submit, and to show her her rightful place: As a busty slut on her knees, her only purpose to service his sizable boner.

On the other hand there was the combination of his sister's intoxicating and addictive futanari cum and the Growth X pills, and with it the undeniable desire for his sisters cock that had been wired into the very essence of his improved body. All he could see, all that he could think of, was Sarah's gorgeous and hulking erection, bending down and trumping his own. And the longer his eyes were glued to that titanic clash of cock-meat, Sarah's throbbing futanari behemoth on top of his own aching manhood, the more that voice in his mind, that told him to resist, became silent. His sister's shaft was bigger, longer and thicker than his own. It was undeniably and completely superior. Size was all that mattered.

Adam remembered how it had felt to have the girl-cock deep down his throat, how full and good it had felt. How heavenly it had tasted and how many earth shattering orgasms it had already given him. His own cock twitched, and a thick glob of precum dripped down to his chest. He wanted, no, he needed, to feel Sarah's gift inside of him again. In any way possible. The voice which tried to resist this truth had clearly lost and fell silent.