Learn English – “woodlump”

He's an elevator operator: his days consist literally of nothing but going up and down—rising and falling. They are therefore "days of rise and fall". That's very boring, so he needs something to "fill" his days and keep them from being wholly monotonous; so he writes in his notebook everything that is not just rise and fall, rise and fall.

The commentator, Mark Jones, is either referencing, or just imitating, the 2018 song "I Might Need Security" by Chance the Rapper. The second verse starts:

I don't get no paper, I gotta sign at the bottom

Still in my bag like the fries at the bottom

Since I can't find an earlier version, my assumption is that Chance came up with the simile, which connects two things:

• The observation that there are often french fries at the bottom of a fast-food bag.
• The slang term "to be in (one's) bag."

"To be in one's bag" means "to be focused" or "to do something to one's highest level of ability" (The Online Slang Dictionary, Urban Dictionary). It's also possible the line alludes to money (as does "paper" in the previous line), through another slang term, "the bag," often seen in phrases like "secure the bag" and "fumble the bag." Though Chance himself wrote an explanation of the line, he did not clarify specifically what he meant by "in my bag."

The majority of American English speakers are likely not familiar with the phrase "in his bag." All of the terms discussed in the previous paragraph are part of hip hop culture and might have even deeper roots in Black English. I don't know if there is a connection to an older use of "my bag" to mean one's personal style or preference, which dates back to the 1960s and jazz culture.

So, what does Mark Jones' usage mean in the context of commentating Curry's shot?

• "In his bag" could mean that Steph is "in the zone" -- focused and making an impressive series of moves leading up to the shot. However, given that Mark Jones is 60 years old and may not be an avid hip hop listener (pure speculation!) he could also have been thinking of the idiom "bag of tricks," which would have much the same meaning here.
• "Like the fries are at the bottom" is the simile, inspired by Chance the Rapper, which connects with the literal meaning of "in his bag." Jones may have inserted the "are" inadvertently, but it (sort of) works either way -- if the fries were at the bottom, one could be (reaching) into one's bag to grab them.
• "Deep" could be referring to the shot (in basketball terms, a "deep" shot is one from far away) or to the not-yet-mentioned fries (deep in the bag).

Lastly, why does Jones use the simile at all? It's a form of emphasis. Even if it's not explicit hyperbole (e.g. "he's driving into the lane with the force of a freight train"), using figurative language adds emphasis for the sole reason that it is less used. NBA commentators use words like "incredible," "amazing," etc so frequently that using something a bit unusual can seem more appropriate in truly extraordinary moments, such as Curry's shot to clinch the win. Another example of a similar phenomenon is Mike Breen yelling "Bang!" after big shots, or various commentators saying "he shoots from <insert nearby city>" instead of "he shoots a long three."