When Dexter’s mother says that Emma’s gift of books is optimistic, she means that she doesn’t think she’ll live long enough to be able to read all of them. She can only address the topic of mortality indirectly, and Dexter himself seems eager to avoid it. “Larging it” is slang for celebrating rambunctiously, often with alcohol or drugs, and so the title of Dexter’s show reflects what he’s doing in his personal life—which is perhaps part of why his mother disapproves of the show.