I've had 4 guys cum on my face. I don't think that counts as a real bukkake though. I would absolutely love to have 10 or 20 guys cum on my face though.
Never had an orgasm cause pains but I've been fucked so hard for so long that it caused pains the next day. But it's like being sore after a good hard workout. It's a good pain that you wear with pride.
In high school I would always suck a guy's dick if he gave me a ride somewhere. It seemed like the polite thing to do and I got the ride I needed and a mouth full of cum so it was a double win for me.
I love when guys cum on my face. It makes me feel like a huge slut which turns me on more. It's even better when there are multiple guys cumming on me.
I got gangbanged by 4 guys and made them all jizz in a glass then I fucked them all again and made them cum a second time in the glass then drank the glass of cum with 8 loads in it.