don't feel to bad OP. I have done this as well, granted it was 14 years ago and I was way beyond drunk(0.36 BAC. actually had alcohol poisoning from that night).
So just remember you were not the first to ever do it nor will you be the last person to ever do it.

To pee in the opening of a soda can you either have to have amazing control and aim or your dick is very small and you were able to fit it in. If he’s able to do that without getting pee everywhere I’m guessing he’s had a lot of practice that’s pretty nasty