Last season, Bruce Jay Friedman's first novel, Stern, was published. It received glowing reviews. Now Friedman's earlier short stories, more than half of which appeared previously along the slick spectrum, have been anthologized as a first publishing venture by Frommer- Pasmantier. And Mr. Friedman distinguishes himself once again, breezing along like an ethnic Raoul Dahl, peopling some ilariously antic situations with a gallery of grotesque memorables, many of whom are minor characters. There's Chico, who snaps his fingers and moans ""Spat, spat. spat, spat. All the while squinting his eyes and hunching over as if he were raining to hear some faint band on the other side of a mountain""; a shriveled, -eyed double-amputee who exudes a faint odor of camphor; a veteran of analysis whosebasic problem is cringing; and Mother Dean, guardian of Rho Delta, ""except for her height, a perfect little old lady"". With few exceptions, these are very, very funny ""entertainments"", in which Mr. Friedman manages to be wildly hip but never recondite. Among the best, ""The Subversive"", ""23 Pat O'Brien Movies"", ""Wonderful Golden Rule Days"", and ""The Holiday Celebrators"".