How to do bbj as safely as possible?

I've always done covered bjs but now sw is legal where I live pretty much everyone is doing bbj. Is there anything I can do to make it safer? I know not to do CIM and to do a health check. Does mouthwash help? Obviously regular testing, of the throat which only one doctor I have seen offers that if you don't ask so I wonder how many people actually do that. Anyway whatever I just want to try be safe. Thanks