"Mark would you pay attention a bit?" asked his mother. She was a great teacher who had originally quit after Mark was born to give more attention to both him and his older sister. She seemed to be enjoying teaching Mark although she wished Mark had asked for her to do this to help with his regular schooling. However with that weird curse he seemed to be on Mark seemed to shrink back socially. At first only during that time of a month he'd become a girl, but then later on just more and more till he didn't even want to go to school anymore. The next school year his mother gave him the option of home schooling which he accepted. Now the kid was about 16, and was about ready to get to college... assuming that Mark would be able to handle actually GOING to a college.
Mark said "Sorry... I'm starting to feel a bit ill and... Well it is around that time..." the now much more timid young man was blushing a bit. Mark got up and went to the bathroom as his gut felt like it was twisting in knots, and this for sure was his time of the month. He took his shirt off as he was getting into the bathroom and starting to feel his nipples start getting erect. She hated the feeling of her nipples on her guy shirts, especially with the growth of breast flesh making them move against the fabric a lot. Pulling down her pants and underwear together Mark was seeing his hips start growing and his waist was shrinking in a bit. Mark panted as his anatomy was being forced smaller in most areas as a lot of the mass was getting squeezed into his breasts and ass as a much squishier type of matter. Panting and looking in the mirror Mark's face was her more female self's and she knew she needed to get on the toilet about now, her penis both hardening as a sensation familiar to cumming was occurring while the penis was shrinking into nothingness. As the cum was evacuating her scrotum which was retreating and turning into her ovaries the white fluid was turning into a more reddish one. As the penis had retreated entirely the fluid started exiting in a large flood.
Panting the girl on the toilet was just cursing that whole curse that seemed to be getting worse and worse each month. Her classmates finding out and snickering behind her back, the whole period thing seemingly getting worse, and her body just seemed to get more and more feminine each month. She then wiped and went to a small cabinet and got some underwear she kept in the bathroom for when she changed gender. Least she knew how to put on a bra now, maybe she should keep a dress or something in there as well. For now she put on her guy clothes which didn't fit well till she got to her own room.
As Mark went to her room she saw her older sister Clara who seeing Mark in her female form said "Oh Mary! Your coming with me!" and then tugged her and forced Mary into her room. Often her family referred to Mark as Mary during her period. Although interestingly enough when they started doing that Mary seemed to stay around longer, and at this point Mary would stay Mary for a little more than 2 days. Despite Clara being older she only barely filled an A-cup compared to Mary's large DD's, but for sure Clara was more socially active and went to the gym making her far stronger than Mark was.
Mary stripped to her underwear and shoved on Clara's bed asked "What the heck do you want with me now?"
Clara tossed her a cute frilly dress to her sister and said "Well my soon to be college bound sister, I got us a double date with some guys at community college." Mary just gave her a look and Clara said "Come on, you need to get more socialization. Your date's also sweet and it wont get that sexual unless you want to I promise."
Mary sighed and said "Well I suppose I am a girl... and should probably at least attempt to talk to another human outside our family." As she started to get the dress on... and while it was really pleasing to the male eyes that was more because the chest was pretty tight, and the bottom of the dress was a bit higher than it was supposed to be as the breasts lifted the thing higher.
Clara said "We should also get you some more girly clothes for you as well."
Later at dinner...