I dry fire my rifle and pistol at a target at a target taped up in my basement, to develop trigger control and help build the muscles that hold the gun up for offhand shooting.
Most of my dry firing is offhand, though I do sometimes lay the rifle across my workbench and fire five to ten times. I mostly don't see the point in "training" to shoot off a bench other than just getting into and maintaining a good position.
With my HD shotgun I will step into one of the rooms in my house (when I am home alone) and dry fire at five different targets as fast as I can. I try to mentally imagine the targets before I enter the room. Sometimes I set them up on purpose. It at least feels like great practice for acquiring a super quick sight picture and squeezing the trigger.