Definition: Used to identify a specific person or thing close at hand or being indicated or experienced; referring to a specific thing or situation just mentioned.
This sign (pointing to the base palm) is a formal citation as a standalone word, but in reality, it's rarely used in signing.
This/it (a determiner in ASL). This determiner is locative, which means that in sentences, spatial reference is variable.
A common determiner in ASL signing is the handshape "Y" for either "this" or "that". And, the other common sign is "THAT-ONE" (a gloss that it's not really "ONE").
A gloss symbol for "ONE" is IX (indexing).
Gloss: SINCE(aah) ME BORN+GROW-UP(aah) THAT/\ ME TELL-OTHER++ NEVER(em)
English equivalent: I've never told this anyone else in my whole life.
The mouth morpheme "aah" along with the movement (slightly slow) in these two signs has a meaning that may be easily missed. This whole sentence has intonation (emphasis) that is conceptually equivalent to the English sentence.