Two persons who are shown to be mutually into each other. That is to say, don't add this tag if one of the group is uncertain or shying away.
Notes
Do not add this tag based on canonicity. A picture with a canon couple who are not doing anything couple-like should not have this tag.
Do not use this tag for all pictures with consensual sex/happy sex. There must be indication that the two involved are in love or have affection for one another.
Both persons must be present in the picture. A hand or a penis is not a person.