Probably best to break it to them gently.......
"You know, you're a really nice girl an all, and you know I like you don't you, but you got some real kipper crotch going on there - your twat smells like the bins at Grimsby Fish Market and it's putting me off my Tuna sarnie, so in the nicest possible way, can you fuck off and jetwash your clam!"
Hope this helps