For the past seven years comedy writer Eddie Gorodetsky has been making wacky-tacky Christmas music tapes for his friends. One compilation fell into the hands of a record company exec, who asked Gorodetsky to produce a Christmas collection for stores. Christmas Party with Eddie G. on Strikin' It Rich/Columbia, combines offbeat holiday songs the hot-rod pop of Untamed Youth's ''Santa's Gonna Shut 'Em Down'' and the Latino bounce of Augie Rios' ''Donde Está Santa Claus'' with comedy bits and '50s radio jingles. The collection, in Gorodetsky's mind, is the soundtrack for a party on the other side of the tracks. ''While the parents are having their cocktail party and listening to the Harry Simeone Chorale,'' says Eddie, who's head writer of The Comedy Channel, ''the kids are in the basement dancing the frug and making out to this album.''