Make sure that you follow the taming procedure correctly :
- To tame the corresponding fapet please check it's taming recipe and do an h act while near a taming spot with at least 3 stamina points (just like in story mode at Black Tamer's barn, on teaching how to tame a bunny then how to make her follow).
here's an extra reference : https://www.pornhub.com/view_video.php?viewkey=ph6396357d71bb9&t=1846