Another one I don't expect to be popular but maybe a few people will really like it. If you don't want nuts then you might need to put "testicles" in the negative. The dataset had a lot of balls. Oh also "tail" so you might want to put that in the negatives too.

In summary:

Trigger word(pony): double_anus

Trigger word(Illust): twin_exhaust

Helpful negatives: tail, testicles