No, keep quiet

You've already put down your signature, and figure that you may as well ride out the tests you've agreed for. The doctor lingers for longer than before next to the cabinets, mixing various liquids between the sets of test tubes. When she turns around, she's holding a grand total of three syringes, and her expression leaks the feeling of excitement.

"It's been a while since someone agreed to this, I've needed more data for some time. It'll feel pretty slow, but trust me it'll be over before you know it. Ready?" Tentatively, you nod, and it's all the succubus needs as encouragement, plunging one of the syringes into the skin of your arm. Her other hand takes another syringe, injecting it directly into the side of your breast. A few seconds later, both syringes are empty, and she takes the third, driving it into the skin of your groin, several inches above the exposed button of your clit.

You can't help but watch your clit as warmth spreads through your body, and as a solid mass of the heat centers directly in the tender button, it starts to grow, multiplying in size and pushing outwards and down from your body. A thoroughly unpleasant sensation follows, as you feel your pussy literally closing up, skin sealing itself from the bottom out. When the feeling passes, and the skin underneath your growing clit is smooth, it stays that way for only a second, before a pair of bumps appear and start to grow outwards in tandem with the above organ.

At the same time, your breasts deflate, falling into your chest and shaping their flesh further into a broad chest. You feel your shoulders broadening, arms and legs strengthening. Your head starts to shift, changing from the soft, smooth features of your prior face into a much more straight, angular visage. Much of your hair starts to fall out, landing on the ground below you, but your hair doesn't quite get sparser, just shorter, going down to only two or three inches at its longest point.

Leaning back up to take another look at your groin, you're more surprised than you necessarily should be to find that your clit has expanded and changed shape to become a flaccid penis, several inches in length. A pair of small golf ball sized balls hang down just below its base, and even as you look down at it, it starts to twitch up in arousal.

"Is... is that it, then?" You ask, initially surprised at the sound of your own voice, much deeper and more gruff than before. The doctor walks over, having watched the entire transformation from a ways away, and gently slides a hand over your new cock, teasing it into an erection.

"Well, it can be. There's a few extra tests I can run for this one, but they're a little... rough around the edges." The doctor's smile is sincere for possibly the first time, and there's mischievous glint in her eyes. "What do you say, would you like to be extra helpful?"