As my dad explained it, there are no secrets but some of the rituals.
Shhh.... I read his books and imho it was a grownup version of the kids clubhouse.....
When mom died dad wanted her wearing her eastern star pin.... I brought out all the pins she had and dad selected one and we gave it to the funeral director. After the funeral, the director handed back her jewellery because it's not encouraged to bury with it on. Dad realized the the pin he'd given for mom was actually his Masonic pin. I quipped well mom always said she felt like a brother..... she had done a lot of support while dad was secretary of the Lodge.....
I knew what she meant when my dh became treasurer for the same Lodge.....