(My friend gave me this idea. :3)
-so to set the scene it's raining. Mirio and Tamaki are at Mirio's house. I'm giving Mirio his own house as he is 18 and well yeah-
Mirio: *asleep*
Tamaki: *in a different bed*
-thunder and lightning-
Tamaki: *jumps and starts panicking* *crying*
Mirio: *wakes up* 'huh-?' *looks over to Tamaki* oh god. *runs over to him* Tamaki! *hugs him tightly*
Tamaki: *hugs him back*
Mirio: what's wrong? Is it the storm?
Tamaki: *nods*
Mirio: it's okay. I've got you. *sits on the bed with him*
Tamaki: *relaxes slightly*
Mirio: why didn't you wake me up?
Tamaki: b-because you l-looked peaceful. I-I didn't w-want to disturb y-you.
Mirio: I don't care. You wake me up if something like this happens. Okay?
Tamaki: O-okay.
Mirio: good. *kisses Tamaki's forehead* you gonna sleep?
Tamaki: *shrugs*
Mirio: *picks Tamaki up and walks over to his bed*
Tamaki: w-why?
Mirio: my bed is bigger.
Tamaki: f-fair.
Mirio: yes. *plays with Tamaki's hair*
Tamaki: *relaxes*
Mirio: UwU
Tamaki: *giggles*
Mirio: U///w///U
Tamaki: heh. *yawns*
Mirio: *lays down pulling Tamaki down*
Tamaki: *has his head on Mirio's chest* -////-
Mirio: *still playing with Tamaki's hair* go to sleep. I'm not leaving.
Tamaki: y-you promise?
Mirio: yes.
Tamaki: *smiles and falls asleep*
Mirio: sleep well. *falls asleep after*