Akaya Akashiya Ayakashi no

From the manga habit:

A dream filled with red camellia and the passing of a strange mask... The owner of this mask is a boy named Yue who lives in a temple populated with unusual - and not altogether human - residents.

It's winter, and the nearby town, Utsuwa, is holding a seasonal festival. Kurogitsune, Yue's fox spirit friend, decides it's the perfect opportunity for the sheltered young man to experience the sights, sounds, and (most of all!) the food in the outside world. Even though Yue is forbidden from ever leaving the temple, they sneak into town, not realising what they've set into motion.

Note: #10 is an extra volume. The main story ends in the 9th volume.