How to tell someone about their hygiene ?

So guys I never did a one night stand before but I was so up to do it with this one guy. So he got a hotel and you know I'm mentally ready to put it down and change his life. So before sex I like to do a little fore play. As I'm going down I feel it and I'm like okay, it's a pullback ( nothing against it). Im about to give head and I pull the foreskin make and this odor hit my face and at that point I was turned off. I shut everything down by making up a lie but the thing is, should I let him know but I'm pretty sure he knows because that scent can not go unnoticed. But if I am the one to tell him, I should I come about it without being disrespectful?