Hi,
Sherwood has exclusively developed two, second-stage moisture-retention fins for the Oasis that keep your mouth cool and comfortable all-dive long.
Welcome to Sherwood Scuba!
I don't know if this is enough in your case... In sport shops you can find soft containers with a pipe to put in a rucksack in order to drink from the pipe. I am pretty sure you can fit on of those container in your BCD pocket and if you press on the container the liquid should come out.
Maybe A little less hygienic: being emerged in water, it should not be difficult to take a sip of it.
If the first solution is not enough I would go for the second but I would not give diving up.
Mako