Nanning is a city in China and the capitol of Guangxi Province.
From the Guangxi Daxue (University) Busstop take the Bus Number 76 all the way to the last stop Langdong Bus Station 琅东汽车站. Walk to the right side after you leave the building and cross the junction, then you should already see the toll station. From there it is super easy to find someone going that direction. User Ruebezahl got even approached and asked if he want to come with the driver to Liuzhou, before he could ask anyone.
South-West towards Vietnam border.
From the center of the city, take bus number 5 to the bus stop just after you turn onto Nahong Avenue. After getting off the bus, walk south along the motor way for about 20 min, passing through a little forest before emerging at the gas station and toll gates at GPS location 22.748040,108.271346. We had a ride in 10 minutes with a sign at the exit of the gas station.