How about three Boku no Pico and the truly beautiful sequels Pico to Chiko and Pico x Coco x Chiko
There isn't much hentai though. It's mostly about Pico's journeys throughout the world, meeting new people along the way and growing stronger with the help of his new friends. It's really heartwarming, if not for the sexual scenes it'd be a wonderful family anime. I'm sure everyone who has seen it can agree fully.
