He doesn't felt the need to.

"Oh yes, this body is quite sensitive. A simple touch sends shivers down my spine toward my my." Said Grayson in his monotone voice.

"Yes say it down where." Commanded the Mad hatter.

"Toward my vagina."

"You are a woman now and this completely normal to have a vagina. You are not an average woman. You are a woman with needs. Can you feel how horny you are right now? Your vagina felt so empty doesn't it?" Said Tetch

"Yes, but I can't understand why I'm so turned on right now. My vagina felt so empty it needs to be filled." Continue Nightwing in trance not realizing that his real body strapped to the table had begun to morph.

"Now I want you to remember. Remember all those time you had sex with men and women. Remember the times you fell to your knees and sucked on a big dick. All those time you milked a cock with your lips or breasts and it sprayed you all over your gorgeous face and breasts. Remember how proud you were. Remember when those cocks invaded your pussy or ass holes and you were panting like a bitch in heat. Remember all the orgasms you had rocking your body to oblivion." Commanded Tetch

"I remembered it all now. I'm such a slut in heat all the time."

"Yes, you are a dumb slut. You don't need that brain of yours when you can use that body. Feel now your intelligence being drained away and replaced by an insatiable lust. Your libido is so strong now that you felt the need to cum at least four times a day. Now tell me how do you feel Dixie." Asked Tetch to his victim who's body was changing in front of his eyes.

"I need to fuck. I can hardly think of something else. All my body is tingling for it." Answered Grayson