How do I *nicely* ask my boyfriend to brush his teeth in the morning

I know this might sound snooby and truly I don't mean for it to. I happen to be a very like - germaphone, perfectionist type person.

Anyway - my boyfriend doesn't brush his teeth in the morning, ever. Its fine he's a grown man but the only thing is when we are together it gets really gross to kiss in the morning. Obviously I don't expect him to do it immidiately after waking. Idk it just really gives me the ick and I feel bad turning away from his kisses. His mouth just gets really slimey from not brushing in the AM. When I tried to ask him originally, he told me he only brushes once a day, and that he wouldn't be able to remember to do it twice. He also acted like it was a big deal.

So I just wanna know - how can I nicely tell him that I am kinda grossed out when he doesn't.