Lmao!!!!..Dude you bring a pee bottle in your pocket or something....Man this could have been all been prevented if you just used the public rest room. Yes its nasty but you could have that paper over the toilet seat.
I would wait till things cool off, because its seem that you really like this girl. Then call her back and expalin what happend. Lets hope she finds it funny, like i did and accepts your appology.