Can't give you the latest, but here is some old data.
Punting in China is actually not that easy. And it can change fast - sometimes the authorities crack down. Great agencies do exist, but they can vanish overnight too. Are you with any locals that can help?
Ok it is not quite punting, but one safe thing to do in all these places is a massage with happy ending. Almost any of the big bold glossy massage places that are lit up like Vegas makes their money from this side of the business. Again, if you can get a local to suggest the right place, all the better. Might be less 'weird' asking a contact for the right massage place than for the right agency. One I used to go to had the best girls on floor six. My local contact sorted it out for me the first time, then on return visits I just told the receptionist I wanted floor 6. Got OWO once or twice in these places, but not FS.
Another thing is KTV girls. (This is karaoke, but little spinners will drink and sing with you, as you play the dice bidding game. Again - easier to go with a local). Google translate is your friend. If you drink with a KTV girl, you can ask her if she wants a drink back in your hotel when she gets off. Had a fair few that way.
If you can get from Shenzhen to Hong Kong it is easier. HK is a punting oasis. (or even better Macao).
In the places I went, I did incalls in massage place, but sex just outcalls back in my hotel (KTV girls and agency). My agency tapes are too old to help.