i think that's the joke, that any rules are nonsensical and arbitrary. i mean, i'm not really aware if any, but in thinking about this it occurs to me that if i'm steering a female around in an unfamiliar place, i put my hand on her lower back to guide. but with a guy i do it more between the shoulders (usually). i never noticed before or thought about why that is. but i also have put my hand on a guy's lower back and didn't think about that either and no one freaked out. so. i don't know that this is a real thing. it isn't as far as i'm concerned