"Sex is very good."
God is telling us the story of who he is through the lens of the things that he has created. This means your humanity is a big part of the storyline, for you have been designed sexually (we are made male or female). Your sexual appetite is therefore a marker, a reflection of the reality that we were made to enjoy a pleasurable relationship with God.
Good sex is therefore very good. The kind of sex that occurs within the bounds of a relationship that also reflects who God is and what He has accomplished through the cross. Marriage.