Boyfriend wants to eat it from the back???

So, my boyfriend really wants to eat me out from the back but I feel like his nose would be...in my ass..😂🙃 I just think it’s unsanitary and maybe won’t smell the best??? Idk..I’m really self conscious about it. What should I do to make sure it smells extra good?(besides showering obviously). Tips would be much appreciated!! My boyfriend has been asking to do this for about a year 😅