へそが茶を沸かす

へそがちゃをわかすhesogachaowakasu

expression · godan verb

1. what a joke!
2. don't make me laugh!
3. to split one's sides laughing
4. to be convulsed with laughter
5. one's navel boils water (using the heat generated by laughing)

Study it in Yanamino