Quick back-story:
Daddy took his little girl (dom/sub relationship, no incest) to a special doctor because he felt she was at an age where she should have her vaginal and anal areas evaluated "for health reasons." When the thorough examination is complete (another fantasy in itself), the Doctor tells the Daddy he is concerned about the lack of elasticity he can feel in both her rectum and vagina. He felt that the anal/rectal therapy needed would be more difficult and lengthy, so it should be started as soon as possible. The Doctor gives Daddy very explicit instructions on a dilation therapy that he would be required to perform at minimum once per day - ideally 2 or 3 times. The instructions are accompanied by unique looking set of what he calls the "rectal dilation therapy devices," There are 8 in total - all the same length, increasing in diameter: .75" ; 1" ; 1.5" ; 1.75" ; 2" ; 2.3" ; 2.5" & 2.8"
The doctor would make it very clear that Daddy would always need to wear tight latex gloves during the therapy sessions to reduce friction.
Also, plenty of (but not crazy amount of) lubricant needs to be liberally applied on all reachable parts of the anus and rectum. Further instructions were given on a typed document with step by step instructions, timing of each element, and suggested dates for completion. (I will definitely write this full exam and aftercare/therapy fantasy in detail soon)
For now, I'm thinking...After a week or so of daily/private therapy sessions, Daddy had been able to successfully complete the required level of acceptance of the first 4 dilators. In my fantasy, success is determined only after the submissive little girl both endured and showed genuine eagerness to accept the various stimulants & violations of her most private parts. It would be important that even in much later sessions down the line- he would start slow and gentle, but consistently and firmly challenging my hole without being too aggressive until my anal ring it is visually loosened. To achieve this, the patient would have to endure both shallow and deep probing stokes of the dilators, slow enough at first but steadily increasing in rhythm and force until you are brutally shoving the cylindrical device all the way in and all the way out until the anal and rectal walls were no longer contracting and jail.
That in mind, I began to think about what it might be like to be naked in bed when my daddy comes home and into my room with gloves, lube, and a dildo saying sweetly "hi baby - Daddy needs to give you your rectal therapy before you go to sleep - remember the doctor told me you need it at least once a day - 2 if possible"
He would calmly but sternly directing me to lay on my side as he put a glove on each hand - lifts my top cheek and pushes my top leg forward to make me more exposed - hearing him squeeze out some lube and rub it around his fingers before touching the outside of my hole - saying "just relax, sweetie, daddy will start slow and we'll work our way up until you can fit this inside you" (showing me the thick dildo) and as i feel his fingers slowly but steadily work on my outer sphincter before pushing one finger a bit more forcefully to fully penetrate my hole, he says "i'm so proud of you sweetie - you have been such a good girl to help daddy perform this therapy - i know it is uncomfortable and can even get painful at times, but your positive outlook" and the dilator tonight is bigger than the last one, and you know part of your treatment is to get used to the feeling of it penetrating you from slow and gentle to very hard and rough. this first time with a new sized dilator is always the hardest - its probably going to hurt quite a bit - you'll be very sore after this session, but don't worry - daddy will sleep with you tonight and comfort you"
... to be continued