each manages to keep the laughter down to a half-suppressed snigger

●Idioms, etc.

each manages to keep the laughter down to a half-suppressed snigger: みんなは自分の笑ひを、忍び笑ひ程度に抑へようと苦心する 丸谷才一著 デニス･キーン訳 『横しぐれ』(Rain in the Wind ) p. 19