It's meant to be a bit silly, but also a bit scary as well. Imagine facing a mouse the size of you! Of course, most mice might be friendly fellows, but the cats... the cats are another matter. Sex can happen, but also try and remember that if you just have sex out in the open, who knows what could happen to you? Be very careful. I might make it six inches, depending on how people feel, and I might go ahead and just let anyone join up.