After a moments hesitation, Tiffany took the vial from Katie's hand and placed it down on the table.
"Tiff, what's u..."
Before Katie could finish her question, Tiffany had her tongue down Katie's throat. Passionately kissing her friend, she started the remove what clothes remained on Katies body with one hand, the other moving down to the crowded scrotum. With a firm squeeze, she caused Katie to moan strongly.
Katie recoiled in shock. Her gaze met Tiff's, her friend standing back, stern with a look in her eyes of pure lust. Both girls proceeded to get undressed in almost record time.
Neither girl took long to get into their stride, bucking and grinding against each other, massaging, licking, caressing, fingering and sucking on various parts of each others anatomy. The curious dance continued, both participants working each other into such a frenzy that each was mere moments from climax. Tiffany was the first to give - Katie had taken her smaller, manageable testicles into her mouth and sucked hard whilst also firmly pressing on her clitoris with her thumb.
Tiffany's climax was intense & loud. It was also messy, as the expected release was replaced with reams of sticky masculine cum, which poured forth from her vagina, squirting in rhythm with the bucking of her hips... Clearly the girls new male appendages were fully capable of delivering their contents via whatever means available.
Katie's torso was caked in strands of Tiffany's 'seed', a fact she was not aware of as the intense orgasm was still working it's way through her system. Eventually she came around and sat up. Both girls were dripping with sweat, despite the cold dank surrounding's of the basement laboratory.
Both girls looked each other in the eyes... "Wow", they both exclaimed in unison.