Cubical is rather light, but not bright. If she is giving you a 'hand' she is standing next to you with your hands at your side (or your hands behind you) if you didn't opt for 'bust touch' service. If you did, she'll press a breast against your hand, and lean into you (so you can't actually move your hand anymore) or not, depending on her mood. If you opted for 'lip service' she'll squat in front of you, roll on a condom, and get busy.
If you walk in knowing the system, head to the counter, order the girl, mention the course you want, slap down cash (only the admission fee- the actual girl will visit you in your private booth shortly after you go there, and you will confirm the course and pay her directly), and have your phone in hand and ready to give to the guy right off the bat, (and can do all of this without a quizzical look on your face) you are very, very unlikely to be turned away.
On the other hand, if you walk in looking like a deer in headlights and ask the tencho if 'foreigners are ok' in English, you are likely to get the 'crossed arms' reply.
We look forward to reading your report!