One of the funniest things that ever happened to me was one time while I was going down on a GF, she was a squirter so I was expecting a flood, she got a bit to enthusiastic and pushed too hard, ended up peeing in my mouth. took a few seconds to realise it wasn't the usual flood.
My cheeks inflated like Tom when Jerry throws dynamite in his mouth, I had to spit, she was still peeing, I covered her, she covered me. The towels we'd put down because she usually squirted were nowhere near man enough for the job.
She was horrified. I tried to laugh it off but she just couldn't even look at me for a few days. It took ages to get her to see the funny side. Apparently my face was a picture with the wide surprised eyes and bulging cheeks before I coughed and sprayed it everywhere