The Cock-Growing Serum. She uses it on herself and facefucks Nightwing.

"I'll take the cock-growing serum." She points to the vial with a desirous look in her eyes.

Calendar Man grins, "Very well." He opens the glass case and the vial and a syringe to the redhead. "Use it wisely." He then gestures to the door, "I hope you enjoyed your party, but it's time for you to move on."

Immediately, Batgirl removes her strap-on and injects herself with the serum. She feels a tingling build in her crotch until, suddenly, her pussy reshapes and forms into a massive cock with a pair of balls. The feeling of her genitals reshaping is intense and strangely euphoric. Batgirl looks down at her newly-formed cock and smiles. Her attention then turns to Nightwing still restrained a several feet away.

Batgirl walks over to her heroic comrade and stands in front of him, her hard cock staring him in the face. Nightwing looks up at Batgirl in confusion, "What the hell are you doing, Ba--" Before he can finish, Batgirl shoves her huge cock into his mouth. Nightwing mumbles, trying to speak, but the vibrations of his voice only make Batgirl more aroused.

She begins facefucking Nightwing, thrusting her cock in and out of his throat and making him gag with every thrust. His eyes water as he continuously takes the huge cock into his throat. The sensation of Nightwing's tight throat around her new cock is too much for Batgirl and she pulls out of his mouth before covering is tired face with her thick, warm spunk.

Nightwing pants heavily as Batgirl's jizz drips down his face. Batgirl smiles and whispers in his ear, "That was fun. I hope you like my new dick, Dick. We're definitely gonna have more fun with it after all this is over." She then walks out the door into the next area.