Subaru hates waking up in the morning. Even though he hates mornings but can deal with the ones where there is no rush to go anywhere; Subaru, hair plastered to his face, can wake up to Yasu's fingers combing through his hair.
There is no train to catch and he can hook his foot over Yasu's leg and coerce him back into sleeping more.
Subaru knows he can, maybe, get another ten minutes before Yasu becomes more insistent.
Yasu will probably start poking Subaru's sides or make (idle) threats involving a pitcher of water and soaking Subaru. Subaru will peer, unconvinced and eyes slitted against waking, at Yasu and Yasu will grin--too happy for this early in the afternoon but it rarely fails to get a tiny lift in the corner of Subaru's mouth.