Casual sex is like Casual Friday: It's casual, but there are still rules. While I'm not here to promote casual relationships and tell you that everybody should be engaging in no strings attached sex, it's definitely a. But then, like every kind of relationship, this one comes with its rules and Here are some absolute no-nos if you are in a casual sex relationship. Casual sex is like Casual Friday: It's casual, but there are still rules. Nothing about sex is “ casual ”. Sex is the most intimate act. Communication is essential, without communication the question is not “if” a disaster. Every type of casual sex —uncommitted, unemotional, purely carnal—is governed by the same rules. Here's how to fornicate properly.