The 'Happy Snacker' text in the image is in reference to Airi, the girl on the left. She's an idol, who had the nickname 'Happy Everyday', and the 'Happy Snacker' is some sort of idol skill thing she that makes her really cute whenever she eats something. The other two characters are her are fans of her which is why they're also doing it. That's a lot of context that I didn't know how to translate, hence this comment