Gau the Umbreon finds himself in a rather needy situation after 'accidentally' consuming a amorous seed which are known for making any who consume them almost instantly become uncontrollably aroused, as if in an incredible powerful heat. Explained better here: https://e621.net/posts/1826285

Also for why she can use psychic on a dark type, see my logic for this here: https://www.furaffinity.net/view/31725506/ (was on e621 but deleted after 31 days >.<)