JJ brings back good memories
If you are in Seoul for a while - JJ may be a good place to find a fuck buddy. ONS is a matter of luck and how handsome you are, but if you don't have time to play, then this is not the place. No obvious pros there despite reports from other sites.
Managed to score phone and contact of a kimchi there sometime ago. Hot babe, working as a personal trainer and had spent tons on drinks. But as I was in and out of Seoul at that time, did not manage to see it through.
Must say most girls are hot and dressed to kill, but there are a few groups of guys and girls just out for drinks and music. Music is usually good as well so even if you are not looking for ONS, just chill out with the music and eye candy.