I know a lot of people that have had success with the citronella collars. Personally, I just got a pet corrector bottle that I spray when Geno acts up. It's basically a can of compressed air that makes a loud hissing sound. He HATES it. Now I just say "Pet Corrector" and Geno immediately is at attention and ready to follow any command I give him, which is nice cause now I don't have to worry about actually having the spray bottle on me.
Last night, Geno and his sister were acting up while I was trying to fall asleep. I just sternly said "Pet Corrector" and Geno looked at me, and I told him lay down on your bed. Down on his pet bed he went...our little girl though doesn't have the same effect. She still tried playing around so I had to pick her up and calm her down a bit but for Geno, it works wonders
Geno is only 4lbs so I am very hesitant to put a collar like that on him. Now that we found out he has the onset of CT, I'm glad I didn't. I was looking into getting a vibrating collar which has a similar effect of a shock collar but it doesn't hurt them. If your dog is a little bigger, like 8lbs+, I'd look into one of those as a possible alternative to the citronella collar. The vibrating collar is also good to train with so you could use it for barking and other things as well.