There is a scene where a character is trying to be level-headed and professional. However, something happens that is funny to him. He lets out a satisfied chuckle but tries with partial success to hold it in as it is not entirely appropriate. The whole process is mostly subconscious. The viewpoint in the scene is a different character.
How can I describe that concisely?
He stifled a satisfied chuckle.
He suppressed a satisfied chuckle.
but I'm not convinced that sounds good, or that it means exactly what I intend. What are some other options?