Could you please help me?

I don't know how to search for a specific threesome content. I would like to search for human on anthro images that contain one guy and two girls; the guy and one of the girls would be human, the other girl would be anthro.

Your help will be appreciated in advance.

Are you looking for a specific picture? If so, use this thread: https://e621.net/forum_topics/23835

Or are you looking for any picture with that kind of content? If so, I don't think there's an easy way to search for something that specific. Maybe group human_on_anthro male/female, though it will include other things than 1 human male + 1 human female + 1 anthro female.