He just asked. LMAO, sorry, let me answer this seriously. I actually really love this question.

Mia (Puppy) was the first of the Menagerie to suggest being branded by Grayson, as it was something she'd been interested in for a while. Grayson was delighted by this suggestion and readily agreed. He spent a LONG time researching because he knew he wanted to do it himself, but he cared very deeply about doing it well so as not to cause great bodily harm to Mia.

During this phase of research, he researched the various methods of human branding and contacted and met with several people with experience in scarification and branding humans. Alice (Kitten), not one to be left out, told Grayson she also wanted to be branded. He chose to multiple strike brand them, a form of burn branding where a thin piece of metal is heated with a propane torch and pressed to the skin in small sections. He had a stencil of his initials made (GW, my profile picture on most social media) and settled on the right hip as the placement of the brand.

Mia went first, and with Alice present, Grayson carefully and slowly branded his initials into her skin. This happened in the playroom and would be the first of all the branding ceremonies. Alice was branded the next day, as she wanted her own special moment, and, like she was there for Mia's, Mia sat in on Alice's branding. In fact, she took photos of the event.

The next addition to the Menagerie was Elsie (Piglet), and it took a little convincing for her to agree to be branded, but in the end, Elsie never wants to disappoint Grayson. Alice and Mia both having brands also helped her be nudged in that direction. Alice and Mia were present for her branding, and again Mia took photos.

After Elsie came Dove (Bird). It was not difficult to convince Dove. She's a masochist to the highest degree. She said yes the first time he asked. For her ceremony, Alice, Mia, and Elsie were present, and Mia took photos.

The last addition to the Menagerie is Juliette (Bear Cub), and she was branded the day after her 18th birthday, which would inevitably be the reason Mia left. She was open to being branded, but very nervous about it. She got lots of reassurance from Alice before she was branded. The rest of the members of the Menagerie were present, and once again, Mia took photos of the event.

They each have a thin, gold necklace with their animal namesake as a pendant. Elsie, Dove, and Juliette first had their collars welded onto them, another skill Grayson taught himself in order to put permanent jewelry on his pets. When they were branded, Alice and Mia already had their collars on. The event became more ceremonious with each addition to the Menagerie, Juliette's being an event with all of the girls wearing their velveteen animal masks and chosen color like they do during their monthly dinners. If this all seems a little cult-y to you, it should!