This comes from the Aphelios mains subreddit, and personally, I think it is a fantastic idea. That said, considering how differently he must be coded, I have no clue on how easy this would be to implement.
Basically, pressing E makes Alune say the name of the next weapon in line. Other people also suggested it gives you a visual cue as to the current order of your weapons.
This not only makes sense from a gameplay perspective, increasing clarity for the player, but also from a lore perspective, since the 2 characters' minds are linked. Surely, Aphelios aught to ask every now and then what his next weapon will be, right?