I accidentally snowballed myself in a manner once. True story.
Me and the little lady were engaged in frantic, quiet, lovemaking in the dark while staying at my mother's house, silent save the slight creaking of the bedframe to avoid waking anyone else in the house. Unfortunately having not had it for a few days in combination with the Stiffette winding me up terribly before finally allowing me to penetrate her, I came much quicker than usual. I knew she hadn't had an orgasm of her own so the second I climbed off her, I started rubbing her clit furiously and then progressed to two fingers with thumb on her clit. As she squirmed beneath me I was so insistent that I would return the favour, I realized properly wet digits would be kinder for such vigorous fingering so without even THINKING about what I had just done, I put my first two fingers in my mouth and swirled them fully around to gather as much saliva as possible. inadvertently lining the entire inside of my mouth with my own population pudding. She realized before I did what had happened, and when her body shuddered I had to check it was at least partially in climax and not just because she was pissing herself in silent laughter.
As for my cum in my own mouth? It wasn't unpleasant. I wouldn't ask for it, but any girl ever tries to kiss me afterwards, I certainly won't use it as a reason not to. Within the last month alone, I'm sure the girl I was with could taste her own asshole on my tongue as we snogged before moving onto Blow Town. Fair's fair after all.