Well apparently cats pupils change depending on the time, so I headcanon that Magnus’s eyes do this as well, and Alec just stops carrying a watch and uses Magnus’s eyes as a clock instead.
What always happens to me:
Me, feeling sad: maybe I should look at some TSC textposts to cheer me up.
Me: *scrolls through and has successfully been cheered up from the really funny ones*
Me: *sees a long text post about Magnus forgetting Alec after he dies*
My brain: DON’T DO IT. DON’T DO IT. DON’T DO IT.
Me: *reads it*
Me: *is once again crying*