so far in the closet they were sitting on Christmas

A figure of speech meaning that you are being such a concealed person of the LGBTQIA+ Community (known as "closeted") that your metaphorically sitting on stuff at the back of the closet, AKA seasonal decor. (See also "you should be pretty fashionable with how long you've been in the closet")

"Everyone kept wondering why Alex never talked about their personal life, but we all knew they were so far in the closet they were sitting on Christmas."