Step 1: Go to any place with lots of buildings and bright lights.
Step 2: Look up and find a sign that says 안마, usually in big red letters.
Step 3: Walk in, pay the money, follow the attendant/s. If you go to one somewhere like Gangnam it will be more expensive but the girls will be hotter. You get what you pay for. Enjoy not being refused service because you are are non-Korean. Thank Jebus you were born into the pure-blooded Korean race.
Step 4: Enjoy the best two hours of your life. Fall in love with Minhee.
Step 5: Repeat until you have no money.
Step 6: Look for an ESL job to maintain your hooker habit.
Step 7: Complain that hagwons only want white teachers.
Step 8: Try to save Minhee from a life of sexual servitude. Fail because she'd rather suck cock for handbags.
Step 9: Return to the US with a broken heart and a cocktail of antibiotic-resistant STIs.
Step 10: Tell all your friends that Korea sucks because it's racist and the girls are vapid materialistic plastic surgery-ravaged whores.
Haha I'm just joking, found this off Reddit. I have been to Seoul and it's lucrative there, definitely not as open as it is here. I didn't try while I was over there, but I read Busan or Gangnam is better for finding escorts as Seoul has alot of tourism and policing is more strict there. Not that you won't find it if you look, but will require more digging. Also be prepared to pay a "foreigner tax" just like Japan, Korean agencies and escorts typically will charge foreigners more than the locals. Do some digging and you'll find some suitable prices for yourself. But don't be alarmed that you have to pay more, it is what is and how it's always been. Good luck man! Seoul is a great place, tons of things to do, amazing food everywhere and very friendly culture. Have fun.