This one is well-hidden. On the road where the black limo is parked, there is a door behind it leading down to the Punk-Pond bar. Go down there and you'll find that the brown door loading inside is locked. Try to disarm some of the guards or fire around to make a lot of noise and a guard inside should open the door for you. Once you're inside, go left and enter the bathroom area. Go up to the toilet on the left and look inside it to find the cheese.