My method was vet -approved. Get a comfy nylon collar (I got ones with a "stretchy" bit, but Oscar hooked his lower teeth in the collar while grooming - TWICE! Thank God I was there when it happened!)

And I put a little shot of Feliway right on the collar..gently squeeze so a little bit soaks into the collar.

Once in the morning, and once at night.

Took Oscar several days to get used to me squirting the collar - now I can do it while he's eating!

My vet loved this idea and was going to pass it on to other clients of his.

Might be worth a try.