My mother was the same way. Just handle your business and dont discuss your love life with your mom. How will your mom know you are having casual sex if you dont tell her...All my boys around me are doing the casual sex thing with these girls so I'm not even bothered about what society would think of me since I'd fit right in...it's my strongly principled Christian mother that I don't wanna get grief from.
Just dont bring any one around your family unless you are in a relationship with them.