I think spraying it around your room is a great idea! Almost like cleansing with sage but, taking it a step further or it being the next step after cleansing. Does that make sense?
In regards to saying something whilst doing that, it's also about feeling. For instance, if you want to focus on better sleep or protection try and put your mind to that. Focus on the feeling of what it is to be protected and how it feels when you are well rested.
You can say things to go along with what you're doing but, in my opinion, you have to focus your energy on the desired result. Otherwise, you're just talking to yourself.
Just my thoughts from personal experience!