Trucker Buffet, also known as a "truckstop soup kitchen" refers to organized sexual encounters involving several men engaging in intercourse without the use of protection and most notably with one recipient being penetrated by multiple partners. Trucker Buffets are typically associated with males engaging in homosexual intercourse with little regard to cleanliness or safe sexual practices.
Don't go in the showers, they're still mopping up after the last trucker buffet.