Drain a few inches from your brother to give to Felicia

As you watched Felicia's behind swaying with each step towards the door, plans of growing yourself faded away as you thought of how amazing your brother's wife would look if she were even bigger. Taller and stronger, with more curves and certainly more tits. You wanted to see her grow and hoped the app on your phone could somehow actually make that a reality. You tapped on her name and had two inches of height draining off of your brother to give it to her. You ticked the box for 'Proportional Size Changes' and a box popped up saying something about male to female transfers and how they would still grow breasts and feminine body parts proportionately. You hastily hit confirm, smiling as you saw the amount of height you'd taken from your brother double and update her height to an impressive 6'3". You lowered your phone down as you heard her footsteps in the kitchen, with her feet against the floor growing louder as she walked back in.

"Almost tripped in there, got dizzy for a sec," she said as she carried in the two glasses. She walked over towards you and the difference was immediately noticeable. Her dress looked even tighter against her grown curves, a bit of cleavage now peeking out of the straining top. The bottom hem came to the middle of her thigh and showed off her long pale legs. She held out the glass of tea for you as you took a step back, taking a drink as you tried not to show how delighted you were that this app could actually work.

"You look really great Felicia, have you been working out a bunch lately?" you asked, hoping it would give an innocent enough reason to keep gawking at her body. She looked a little surprised, looking down at herself and fiddling with her dress.

"No, although I think your brother must've messed up the laundry or something. This dress is one of my favorites but it's a bit snug," she said. She continued to tug about and mess with the fabric of her dress as she clearly tried to make sense of why it fit so much tighter. With a smirk on your face you glanced down at your phone, with a few taps on the screen you were hitting confirm to give her another inch of height from your brother, looking up to see her rise another two inches taller. Her tits filled out a bit more and you could see some definition in her arms now as her muscles swelled just a bit larger. She was now nearly a full foot taller than your own 5'6" height, and it was impossible not to get turned on looking at your growing sister in law.

"Well it looks stunning on you. You actually look like you've had a bit of a late growth spurt," you said, causing her attention to move from herself back to you.

"Huh?" she said, "I...have you always been so short?" she asked as she stepped closer, looking down on you by even more than normal.

"I'm five foot, six inches, same as always. I actually think it's you that seems bigger and better. How tall are you exactly?" you asked while trying to hide your smirk. She immediately answered back and said that she was 5'11", but with the massive height difference between you two she second guessed the size that she'd always known, looking confused. She took a step back and you could see that her confusion was turning to a bit of notable concern.

"Uhh, little weird to ask but, would you mind checking and measuring me?" she asked. A quick response of "sure" was all it took and she was heading off once again. As she walked to the kitchen to fetch a tape measure, you once more watched her ass as she left. Now though it was an even better sight than just a few minutes ago. Her dress was shorter and came down to just a few inches below what was clearly a larger rear than before. Felicia was always a curvy woman, but now her ass was more plump than ever, and you delighted in the knowledge that you could change her in any way you wanted.

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