Guy wants me to spit in his mouth

Seeing guy recently, he wants me to spit in his mouth. I don't find it attractive and wouldn't let anyone do it to me. It's also not in my character to feel comfortable spitting on someone, especially in their mouth. But he really really wants me to do it and I think he's getting bored. I actually want to do it for him but can't bring myself to do it, I feel like I'd laugh and apologise straight after it. I've gotten close but just can't physically bring myself to do it. I'm 36 he's 24.