I once saw two cats (male and female) having sex in missionary position. If this wasn't strange enough, there was a lot more cats surrounding the couple and watching. XD As soon as all of them saw me and my girlfriend (at the time), they all ran away. I think there might be a secret cat society where they do and choose what secret things to do far from human sight. Judging by what happened that time, humans were not supposed to see that. Cat eyes only!!! XD