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1.
N. A cocktail containing one part orange soda and one part beer.

Modeled after the more distinguished and sophisticated "Mimosa" which contains orange juice and champagne.
Trailermosas are commonly consumed in the warm summer months at highly impoverished locations by lower-class people.
"Is Sandy over on her mobile-home porch, drinking trailermosas?"

"Come on over to my trailer court for cocktails; we've got trailermosas!"
by Jay Jay Cool Whip May 20, 2011