To get this, you must complete the following:
- interact with the woman sitting near the hog herding pen, by the tree
- dance in front of the stage (merely entering within the radius will make him start dancing)
- have a drink with the dwarves in the small tent inside the barn
- head up to the hayloft of the barn (use ladder on the outside) and interact with the pillows here
- interact with the woman standing near the barn's ladder
- have a drink with the women around a small table (to the left of the initial gate entrance)
The rest are mandatory and therefore not missable:
- search for the fire swallower and dog
- participate in the "Slip in for a Slipper"
- participate in the hog herding contest
- play gwent with the halflings
Once done, go talk to Gaunter O'Dimm and after the quest completes, this should pop up.