So to get this achievement you must first gain access to Satan's party after obtaining an invitation near the start of the game.
Once inside make your way as far right as possible.
Eventually you will be outside and see Satan talking with a demon.
You don't interact with Satan, but instead keep walking past until you see a demon dog sleeping near the edge of the party.
Simply interact with the dog and you will get the achievement after a nearby demon finishes talking to you about the dog.
Please write in the comments if you think I need to edit this guide in any way. Thanks and good luck.