The G-spot unlocks over time. As stated in the patch notes for approximately 0.16/0.17, it's unlocked by viewing the first option on the PC and the latest news.
It will only be a nighttime-only spot. It's also the most efficient place to withdraw the money you need to hack into the dungeons.
I hope my help helps. I have Sector F, but I don't know how to unlock it. XD