At low limits and full ring you should basically only bet if you think there is direct value in the bet. In a multiway pot with draws on the board there is really not much point; every now and then on a dryer or on a paired board you can take a stab against one or two opponents.

Shorthanded you have to semibluff a lot more; however you also have to be willing to follow up on blank turns and rivers. Still at $50 PLO you should not be too concerned about it unless you feel you're not getting any action on made hands. In that case, simply raise a bit more in LP and take some stabs on dryer boards. Most opponents will not be smart enough to checkraise you with air because they figure you're Cbet % is too high.

I think this is something you need to actually think about; any answers learned by rote will be counter-intuitive to your game, IMO. What situations do YOU think you should be CBing in, against the opposition you face?