Barbed wire is no match for canine/equine love.
The mini pony loves that the dog is cleaning its cool face. The dog loves that the mini pony tastes like its dog food.
And I'm not too sure why the tiny horse's hair is standing on end. I know people claim to see sparks and/or fireworks when they kiss the one they love, and hair standing on end is usually associated with electrocution. Maybe dog/mini pony love is different like that.