Futination

A futanari mad scientist, Serene Siren, leads her submissive new test subject, Leana Lovings, into a laboratory. Serene's hypothesis is that continuous sexual stimulation, mixed with just the right amount of futa cum, can trigger spontaneous appendage growth... in other words, if this works, it will cause Leana to undergo a futanari transformation.

Serene positions Leana on the saddle of a sex machine, pulling aside Leana's panties so the machine's dildo can enter her. As the machine's vibrations intensify, Leana's pussy gets wetter and wetter... and her nipples even start lactating! Serene gets so excited that her cock becomes hard, and she has Leana give her a blowjob. Serene eventually blows a load into Leana's mouth, and after Leana swallows the futa cum, she ends up growing her own cock!

Serene is delighted that her experiment worked, and Leana eagerly strokes her new cock until it becomes big and hard. After that, the two futanari beauties celebrate Leana's transformation by having incredible sex. Behold, the power of science!