“Sheltering vocabulary while unsheltering grammar” refers to using ANY grammar necessary to express ideas while limiting words. This mantra has been instrumental in the design of our latest Latin novellas since it simultaneously reduces cognitive demand while casting a broad net of input, exposing students to different verb forms as they attend to fewer “big content word” meanings. Despite this unsheltering, sometimes we have to make a decision about when our story takes place! This establishes a focus—perhaps unwanted—on one tense or another.
If we, indeed, want to expose students to that broad net of input, we can respond appropriately without sacrificing any communicative value. Here are some very practical ways to conceptualize the use of different tenses in stories, and what to do in order to add variety to the verb forms used in stories and readings:
Dialogue
ALWAYS Present
When the teacher interacts with student actors, the dialogue is in present tense—ALWAYS (Seriously, characters don’t talk to each other in the past tense in order to solve a conflict…they might reference the past, or even the future, but they usually speak to each other in real time about something they must accomplish, else, it’s just a conversation that feels out of place).
Storyasking
A) Past
The class discovers, or guesses a story that the teacher knows (or “knows”), and that already took place, so the details are in the past. This feels like a game, and has a sense of intrigue that tends to get students thinking (e.g. “Hey, Mr P says he already knows the story, but will totally add our detail into it if we make him laugh,” etc.).
B) Present
The class co-creates a story unfolding right before their eyes! The details are in the present. Not much changes with this format, and students might not even notice the difference, but I generally don’t feel the intrigue of the “guessing game” when I storyask in the present, so I avoid it. N.B. with dialogue ALSO in the present, exposure for this kind of story is restricted to present tense. If you choose to storyask in the present, DEFINITELY read the Parallel Story, or Class Story in the past tense.
C) Future
Future is awkward; I have zero experience storyasking in the future, but I know that it can work when describing plans a character has, or events to come (e.g. “Suddenly, Pippin makes a loud noise. Surely, the whole mountain heard that. The door will be kicked down by orcs. The army will rush in with great speed and will kill them all!”).
Reading
Past/Present
In order to provide exposure to different verb forms, write stories in a different tense from the class story—whatever it was. Logically, it makes sense to read a known story in the past (because students can recall what already happened), but that logic doesn’t mean much if the goal is to expose students to a broad net of input. After all, students should be compelled to interpret the message content (and not the tenses)!
Also, reading a known story is questionable anyway; there isn’t a communicative purpose in and of itself (see Tea with BVP Eisode 42), possibly resulting in language-like practice (also see Embedded Readings vs. Tiered Readings). Parallel stories are more engaging than class stories because students don’t know the details, but typed-up class stories are still great for building your Free Voluntary Reading (FVR) library. Whatever you do, variety is key.
So, in order to expose students to that broad net of input, the following guide should help keep you honest, or at least avoid using the same tense over and over willy-nilly:
Storyask Read Parallel Read Class
Past -> Present **
Present -> Past **
Past -> Present -> Past
Present -> Past -> Present
Magister P. 
On Fridays I often ask students what their plans for the weekend are. Many times students will reply that they have no plans or don’t know what they will do. I warn students that I reserve the right to have the class plan their weekend for them. Voila! Instant future tense. On Monday we review the activities and ask the (un)fortunate victim – er, volunteer if he/she did each activity.
Rereading is an acceptable practice L1. Two purposes occur to me. 1) We could reread to review or relearn information. 2) We often reread to relive the experience we had during our first reading. In both of these situations we walk away with greater insight and greater appreciation of the reading. The chance of us rereading assumes a perceived importance or interest on our part as readers. A story created by students may not be felt to be important enough or interesting enough to reread it. But having reread many things, I am inclined to say that there is a communicative value.
Good point, although those purpose examples might be more like unicorns in the classroom, right? How many students are interested in learning, let alone relearning? I think the other is more likely, but the day following a story seems to soon…perhaps that’s why I find value in using class stories for FVR…to relive those funny stories later in the year.