According to The Hollywood Reporter, Val Kilmer opened up about his issues with the Baitsuit in “Val,” his autobiographical documentary released in 2021. “Whatever boyhood excitement I had was crushed by the reality of the Batsuit,” he said. “Yes, every boy wants to be Batman. They actually want to be him … not necessarily play him in a movie.”
Kilmer said the restrictive suit made him almost breathless to the point that he couldn’t hear people talking to him. To solve his woes, he said incorporated a little “soap opera” acting that involved putting his hands on his hips in scenes he had with Nicole Kidman. “I think it made no difference what I was doing,” he said. “I tried to be like an actor on a soap opera. When I would turn to Nicole … I couldn’t count how many times I put my hands on my hips.”
Honestly, while I enjoyed “Days of Our Lives” for a brief stretch while in middle school, I’m not that familiar with soap opera acting, so I’m not quite sure of its relation to placing your hands on your hips; Google wasn’t any help. However, I do understand that some deep breathing exercises involves holding the hips. Perhaps, Kilmer used this technique to prevent himself from passing out during his kiss scenes with Kidman. Again, I’m not sure because these scenes were shot close up in a Sergio Leone sorta way, so it’s impossible to see where his hands are. Despite Kilmer’s breathing issues, Schumacher’s Batsuits would be criticized for something entirely different.
Source : https://www.slashfilm.com/1003360/val-kilmers-batman-forever-batsuit-woes-were-solved-with-a-little-soap-opera-acting/