A Harlem man charged with killing his 76-year-old grandmother went on trial yesterday — for allegedly strangling a Brooklyn cross-dresser.

But Larry Davis’ lawyer, Martin Goldberg, tried to pin Richard “Denise” McCoy’s August 2010 death on his request to be tied up after a sex-and-pot marathon.

Last March, relatives found Davis, 22, in bed with a hooker with his grandma Cora’s body stashed in a nearby closet, prosectors say.