I've spoken with a few Korean girls that work in Hollywood area AMPs about this, and they told me that it rarely happens, but every now and then a lady customer does come in. The girls told me that about half of the girls will give massages to the female customers, but for your type of HE, expect only the masseuse to use her fingers, as it's extremely unlikely that she is going to go down on you. AMPhunter's advise makes the most sense - best to locate an independent provider.
I think there about 1 million people who would volunteer to give you a massage and happy ending....it would be fun to go to a place as a couple and watch.....wonder if these places are cool with couples or not??