Mentally still being mostly your mother, it occurred to you that continuing to hold onto her mentality was really quite the violation of privacy. Admittedly, you were being an asshole that picture day, but the point stands that you shouldn't know she felt that way because she didn't tell you.
Just as you wouldn't want a future child of yours to go poking through your private thoughts and memories, it was really not good for you to be continuing to hold onto her mentality... No matter! You could just revert back and then do a full gender swap with a reality change to explore your feminine side a little... heck, a lot more! Better yet, you would get a whole room full of clothes, and toys geared to you being a girl! You could explore makeup, and perfumes, maybe your room would have candles! It was like 16 Christmases and birthday's all wrapped into one!
Giddy with excitement you clicked the reversion button, selecting instantaneous instead of keeping the 5 minute timer his brother had set to change him in the first place. You selected your default profile, reverting everything that happened since you woke up, feeling a little grossed out at the thought of becoming a boy again. Clicking the button you felt the warmth, and started looking through the transgender options to really get into... 'What am I doing?' you stopped as you thought back over the last few minutes...
You were given the mentality of a cisgender woman, OF COURSE you would want to explore your womanhood just as much as your mom did as a teen... but you are a guy, a dude, destined to be a man... If you were to drop your mentality into someone else and make them your age and they'd end up turning themselves into... you bit your lower lip as a smirk developed... you shot a glance at the pile of clothes containing your little brother, he'd almost escaped...
Your mother was 39 now, and she was the younger of your parents, meaning she was 23 when you were born... so if she had you at 18 you'd be 5 years older making you 21! Perfect!
You pulled up your brother's page, set up your protections so that he wouldn't use the device again without your permission and even then only how you approved, all the settings for today's entertainment second, and finally the lasting torment. The timing was perfect.
Ben finally freed himself from his original clothing, his age changed but his mentality didn't, he was a 12 year old trapped in a 1 year old's body and he had already began plotting his revenge! 'I'll turn Jeff into my dog, I'll force him to obey! He'll always have to listen to my commands except he will find himself drinking toilet water even though fresh bowls of water are available and I yell at him to not do that! It'll drive him nuts! He'll be so confused and wonder what's wrong with him.' Ben finally wriggled out of the pile of clothes looking up to see Jeff was back to himself while he was stuck as a baby. Wait, Jeff looked different, older, bigger?
Jeff stood up picking Ben off the floor and laying him on the bed, Jeff smiled down at Ben... Lovingly? "Who's my baby boy?" Jeff coo'd with a chuckle.
The realization hit Ben, he could feel himself regressing mentally, 'No! Daddy is trapping me! I need to do something...' a diaper and onesie appeared on his body making movement harder, he felt weaker, he was becoming an infant! Ben started to cry, though as a newborn, he couldn't make too much noise yet. Jeff lifted him up and started talking, Daddy's voice was soothing and Ben calmed down, not remembering why he was upset in the first place.
Jeff had to watch his little brother anyway today and felt having Ben grow from an infant into a 5 year old throughout it, giving him 5 years worth of experiences of knowing Jeff as his loving father might help him treat Jeff a little better... Reality is changing to make Ben really Jeff's son today, and Jeff is a 21 year old for the day... the real fun will be tomorrow when mostly everything will return to normal...
From now on, Ben won't be able to help but think of Jeff as being on the same level of their actual dad. The fear of disappointing or disobeying him will flit across his mind even when Jeff wouldn't have real authority after today, but equally the elation of getting an "attaboy" or "great work"! To really rub it in, when referring to one another they will both slip up regularly. Jeff will call Ben "kiddo" or "son" and Ben will call Jeff "dad" or "daddy" and only the two of them will realize, everyone else will understand who they are referring to.