Kemonokko Tsuushin: The Animation - Ushi Musume Bell — Episode 1

Bell gives the main character, who is concerned about her short stature, homemade milk to drink, helps her milk the cow, and does such and such things to her in return... The main character and Bell, who has a very plump body, make out together in this animated lovey-dovey work. (Source: Fanza, translated)