One of the best show-stoppers I ever uttered was during my first ever session playing a home-brew with a group of strangers. Two of them were brothers, very rotund, one named 'Tony'. A third player that I later found out was bisexual was 'Dave'.
My character was a mage belonging to a race the GM described as 'hopelessy and utterly decadent', so after I loaned one of the party warriors some of my money to buy a piece of equipment he needed, I told him it was a 'retainer fee for his services'. Of course, being depraved decadent filth, the services my character had in mind were not bodyguard, but more prostitution-related.
A few hours into the session, we took a small break, during which we had an out-grossing contest. Various things distasteful were groaned over, and I could hardly be said to be the winner. But, just as we started playing again, I turned to 'Dave' (see note above), the obvious leader in the contest, and said "Tony, buttsex."
He laughed so hard he puked.