Crowley has Yuu and Yui in front of him as he needs to help them unlock their bird from making him to have a headack once this is over with as he knows unlocking the bird form must be done alone and once you're one hundred and fifty-years-old maximum making him to hate this as he needs to help them out or else they may hurt themselves like he did.

"Yuu. Yui. Hatchlings. It's time to learn how to unlock your crow bird form. Fair warning, what I'm about to show you may freak you out." Crowley said as he removed his outer clothing and fully showed them the feathers sticking out of his body making them to gasp as Yuu shakes her head at what happened to her otou-sama as she has tears in her eyes.

Muscular his body may be and shaped like a sculptor made him perfect, his body has feathers coming out of his body.  Small feathers in the cafes, small feathers in the thighs and close to the hips, Crowley's even wearing a bikini boxer cause of the feathers above his manhood, the center of his chest, on his lower arms and a major on his upper arm and on his shoulders.

The feathers on his shoulders were larger and there's even some on his cheeks making Yuu to hug him not caring his in his boxers, her otou-sama's in pain making him to hug ehr back as he can tell she can sense the pain he's been in for a long time making him to rub her head down and up before going down again as Yuu's upset right now.

(AN: May this be Leander the Crow Child of the Unseelie Court by Northfarthing on DeviantArt, I'm using it to show Crowley's body condition after he had gained his crow bird form, but has some of the feathers sticking out of his body as he didn't have help to learn how to do it properly)

Crowley knows Yuu's more upset as he plans to help them out making him to make sure they don't get hurt when they transform. Crowley doens't want them to be like him as he doesn't know that Professor Crewel was watching the screen in front of him as he sees Crowley's teaching the girls before he saw Crowley's body condition.

'Shit! He's hot even with those feathers stilling out of him!' Professor Crewel thought as he has a hard time keeping himself from just jumping Crowley there and then making him to leave the area and ignore it, but Yuu and Yui saw it and don't mind him as their other parent. Crowley has them to sit cross-legged and close their eyes as they need to find the bird first.

Yuu just closed her eyes and didn't look as she feels like that would be the problem as they might not what to be found making her to ignore everything around her and stay still making her to hear a forest. A forest with a waterfall that has birds flying in the sky, is in the trees and on the ground. She hears the flaps of the wings above her, but they were larger.

Yuu didn't open her eyes as she remains still and just breath in making the birds on the ground to fly up into the trees. She's in a large clearance in the forest as everything is still as if waiting for something making Yuu to wait with it as the large feet on the ground move around her as if the bird's trying to figure her out, then it happened.

Yuu can feel the large beak and it's nuzzling her right cheek, but she still didn't move as she allows it to see if she's worthy since the Crow Faes seems to be doing it wrong the whole time making the bird to crawl and then a flash in the clearance making everything to be covered in white light as if the bird has decided that she's worthy of the giant crow form of the Crow Faes.

(AN: This is Yuu's Giant Crow Form, but it's three sizes smaller than Crowley's since she's still a 'baby' in terms of Faes as they grow slowly than grow like a human)

Crowley was shocked as Yuu looks beautiful and she nuzzles him making him to pet her gently as it seems Yuu's quicker than Yui, but that's the difference between them may they be twins now than someone with a split-personality. Yuu got to Yui and craws making Yui to see Yuu as she opens her eyes making Yuu to nuzzle her face as she's hugged by her sister. 

It's making Yuu to change back and then chanced her clothing with her magic and Crowley had tears of proudness may he hate the clothing as it's not right to wear them at age sixteen and she's still a baby in Fae terms making him to be hating those clothing she has on as he wants them gone right now as he glares at the clothing for existing really.

(AN: Yuu's hair is still the same hair color and the hairstyle is still there, too as her hair got longer to do the hairstyle)

Yuu explains to Yui how to actually find her bird form and that the Crow Faes have been doing it all wrong hence the consequences of the feathers being out of the body making Crowley to be shocked as Yui did the same making her to have her crow form as well, too thanks to Yuu telling her about it as Crowley wonders if he should tell the other Crow Faes about this.

(AN: Three sizes smaller than Crowley's crow form)

Yuu and Yui have their crow forms making it to be easy since they have it at ⁂ making them to gently work with it as Yuu's following the instincts more than trying to force it to work with her as she keeps feeling like she needs to find dead animals to eat from making her ask Crowley about that and he calms her down and explains why.

Yuu didn't know Crow Faes, Raven and Vulture Faes can eat dead things and not get sick from it making her to warn Yui and they tried to figure out out to remove the instincts without harming their bird form making Lilia to smile as they came to him in help of this idea of theirs as they both train making Malleus to watch them.

Crowley's busy with Professor Crewel as they haven't left the bedroom for four days making Professor Crewel to feel stiff, sore and in pain, but that was the best nights ever as Crowley was in he had noticed major signs of Crowley going into heat and he did do research a couple of times and got different answers.

'If they are suddenly more agitated or seem to be trying to mate with everything they can, they are probably in heat. Another way is to look at their physical appearance. If they are fluffed up and their cere is red, they are most likely in heat. heat refers to estrus which isn't possible in birds.'

'Some birds have more extreme behavior changes including territorial aggression, screaming, and/or feather destruction. When sexually stimulated, the bird may strut around, display feathers (wings and tail fanning), become aggressive, and/or become more vocal. Some will bite and chase people around the house.'

'How do you tell when a Crow is displaying his affection for you? One of the ways is by them showing "submissive behavior", such as bowing or lowering his head while still staring right at you.'

Professor Crewel didn't expect this from his boss-now-boyfriend making him to be stiff as Crowley's behind him before mentioning his two hatchlings said about him being in love with him before vanishing to Crowley's bedroom to mate making Professor Crewel to never again complain mentally about Crowley not being in need of sex again.