Even after an extensive exclusion list, the majority of pictures in the dog_days category on Gelbooru featured heavy petting, so some popular characters are sadly underrepresented.
Red half-rims below the fold, because boobs.
Update: I never knew there was a bonus onsen episode from the third season:
[the following picture might be captioned “wow, I still have a spine after that last pose”. Seriously, both halves are nicely drawn, but how does the artist think they’re attached?]