忍俊不禁

Explanation: Ren Jun: smile; can not help: can not control himself. That can not help but laugh. 　　Usage: Partial official; as predicate, adverbial; that can not help but laugh 　　Source: Cui Tang, "A Time of Xuzhou Pu book": "the first step last year, laughing, Qiurong quite cut." 　　Examples: Panda charmingly naive, naughty cute little monkey, so the adults around ~, children are even more laughter. Thesaurus:  be dissolved in [into] tears, be unable to stifle a laugh; can’ t help laughing, Renjunbuzhu, let loose a banquet of brine, tears and mucus flowing down rapidly, naturally, Spontaneously, quiet or partly suppressed laugh Antonym Group:  forced laughter, find happiness in suffering