Jack Griffin covered that when he noted higher physical activity causes greater CO2 production . Plus, to be realistic, the preparatory activities, like showing-off a GMC Sierra for masculine competition, or flying the girl to you from Bangkok to America, would have consequences in terms of CO2 production.
Also, if sex causes you to reproduce, that is, produce more people, it could have catastrophic CO2 consequences.
I'm being facetious. But if you want to be thorough, yes, almost every activity of a human in the modern world produces CO2. If electricity were made using nuclear energy or something "renewable", that wouldn't be the case.