In case anyone is wondering/curious about the manga's title, 'asa chun' is a euphemism for the morning after sex. 'asa' being morning and 'chun' being the sound of sparrows chirping. Imagine waking up in bed with a mysterious girl in your bed, the morning sun is peeking through the blinds, the birds are singing. So basically, the premise of the manga as the title promises is "hey, want to have a morning after with me?" which sounds weird until you read the first chapter. Then you're like, oh okay. Sure.
Well, that's it, that's the manga. Have fun!