API DropItemOnUnit

Drops an item from the cursor onto the specified target. Can be used to initiate a trade session (though see Trade functions) or feeding pets. DropItemOnUnit(unit);

Arguments

 * unit : UnitId - Unit to which you want to give the item on the cursor.

Example
if ( CursorHasItem ) then DropItemOnUnit("pet"); end;

Result
Item is dropped from cursor and given to the player's pet.