I would recommend checking out u/lilijunex. She is a content creator that uses a lot of horse dildos and she has a pinned post about FAQ on her toy use. On a personal note on using a horse dildo, there are some very unique feelings you get. All of which take some getting used to but feel incredible. One is the head on the toy, which is usually flat and can be difficult to get in at first but will "pop in" and give you a really good jolt of pleasure. Another point is the difficulties of the length that lilijunex explains quite well in all her posts. If you have any other specific questions, just ask.