CO2 Agitation Method

Hey guys,

I'm looking for a method that will help to agitate a cold liquid and while simulaneously introducing CO2 into the liquid. The bottom of the container that will have the liquid in it will be sealed and the only access into the container will be through the neck of the bottle on the top. Do you guys have any ideas about how I can do that? Would the CO2 need to be in the container before the liquid is introduced or would it need to be vice versa?

Also, this application will need to be done over and over. My end goal is to have a volume of 3.5-4.0 units of CO2 in the liquid after dispersion.

Thanks in advance!