A futanari mad scientist going wild - Seren Siren and Leana Lovings

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.