Just because you're abroad doesn't mean that you should let your guard down. Like in the Philippines, avoid street walkers, and peddlers offering girls. Sa Japan nga, they drug you and practically imprison you in a Kabukicho bar, paano pa sa Vietnam?
There's no need to engage that much risk just to have sex. As long as it's not a legit spa for foreigners and women, almost all spas in Vietnam offer "boom-boom". Walang hiya-hiya doon. Kahit hindi cubicle type ang kwarto, maraming thera game sa ATW kahit sa CR niyo pa gawin.
You will know it when you see it. Most of us here know naman what a legit spa and a spakol looks like. They're scattered all around HCM and Hanoi, you just have to go around a bit. It's not cheap though. Halos kaparehas presyo dito.