I am not sure this is possible although some of your descriptions could possibly bring out the end result you were trying for. I was able to follow the scenario and had no problem picturing what was happening. I think Justin would have had more of a fearful reaction at the beginning of the process. I know there are drugs out there that could be used to bring about his euphoria but I still think he would have been more frightened. Maybe Mr. C. should push and hold him on the couch as he sat close to him to let the drugs take effect.

The story as is would be possible, but I don’t think you could take it any farther unless Mr. C.’s daughter is in on the depravity. How would he explain the new Justin to her? That’s what is so good about writing though. You can begin and end where you want.

I have included a line-by-line review below:
Red - changes needed
Blue - suggested changes
*** I hated wearing dress clothes but I LOVED (I know you are trying to show emotion here, but it is normally done through the use of italics not all caps) what she was wearing. She had on a white sheer blouse and black velvet skirt with a thick patent leather belt to match her shoes. I was instantly aroused and she complimented my tie, (period not a comma)
***It was Thursday night and I was SO ready for Jocelyn to wear the white lace knee socks and the 6 inch (hyphenated) patent leather bowed toe heels I had bought for her. She was just going to open the door for me draped in a cream colored (hyphenated) velvet cape. I was so ready.
***"Hello (comma) Mister Canter. (comma not a period)" I timidly said as I blushed slightly because my erection didn't fall down fast enough.
***(new paragraph because someone else is speaking) "Hello (comma) Justin. (comma not a period)" Mister Canter replied rather sharply. "Come in and have a seat on the couch, (period not a comma) Jocelyn is helping her Aunt and will be home after midnight which is the time you are usually finishing up with my little girl..."
***(new paragraph) I was instantly terrified but I am an honest person so I decided to run with blunt honesty.
***He told me that HE had not only picked out the tie but the thick patent leather belt I was wearing, the satin boy brief underwear (comma) and the black patent oxfords I had on as well. He instructed me to show him my socks and I pulled up my pant leg to show the silk patterned design. (Why isn’t this boy running out the door?)
***All around the room (comma) there were assorted slutty outfits like lace tops and leather skirts, on the chest of drawers (comma) there were different color wigs and several racks of extremely high heels in all different colors. Mr. Canter quickly brought a liquid covered (hyphenated) cloth to cover my mouth and nose and he firmly layed laid me back on the bed. I was conscious and aware and very, very relaxed. I focused in on myself on in the mirror on the ceiling as he began to remove my clothes.
***The bed was covered in a thick shiny black plastic like PVC and in my state of mind it just seemed so sexy, (period not a comma)
***After I attempted to swallow it he sat knees over my waist (at this point Justin is sitting up so Mr. C wouldn’t be able to place his knees over his waist. Maybe if you mention he pushed Justin back down…) and firmly gripped the back of my neck, his other hand supporting my lower back. … He instructed my me to keep focus and to stare into his eyes. He kissed me. His tongue found it's (no apostrophe) way everywhere it wanted. I was throbbing so hard and he noticed and laid me back down. (Keeping up with the positions of everyone is hard. I use dolls)
***He helped me to my feet and to the gothic looking (hyphenated) chair. He latched my wrists to the chairs (apostrophe s) arms and my legs were cuffed at a height to keep me correctly postured. … I was put in full make up (one word) and a cropped auburn reddish wig. … I couldn't even feel frightened as I received large injections in my hips and ass cheeks and them then countless circling injections in my soon-to-be breasts. I watched wide eyed (hyphenated) as my chest swelled. Mr. Canter put on gloves as he smeared a moss like (hyphenated) ooze on two clamps and evenly applied them to my nipples.
***I was entranced at by the image in the mirror, was like my (period not a comma, caps on My) nipples were little breasts on the top center of huge breasts. …. "Don't worry Jissellynn (comma) my dear, I'm going to take care of you worrying about that for a very very long time." He took out a urethral tube and lubed up the tip and attached it to a short hose that was fed by an enormous 2 quart (hyphenated) syringe containing a thick pink fluid. …By the time your own urine dissolves it though through your system (comma) you will be so small weak and flaccid we will not need the cage any longer. We will intentionally play with your clitty and make you play with it and eventually (comma) it will become clear that it will be about the same size as your new nipples but no where (one word) near as firm."
*** I pushed my tongue against my bottom lip, puckered my upper (comma) and softly opened my mouth like a beckoning pussy.

My review has been submitted for consideration in "Good Deeds Get CASH!" .