A ocásek ti měl takhle dlouhý

Gramatika: The dative tiis a so-called the "dative of contact"; it is used by the speaker to engage the reader (addressee) in a conversation; here Čapek is telling Dášeňka to imagine Foxlík's fantastic long tail vividly as if it were in front of her eyes. Dative of contact is used mainly in informal (i.e. not official) conversation.