expression, godan verb (-su)
look triumphant; flare one's nostrils with pride
Idiomatic expression describing someone's nostrils flaring slightly in a self-satisfied or triumphant manner, often when feeling proud or superior.
彼は成功を自慢して、小鼻をうごめかしながら話した。
He talked about his success, flaring his nostrils with pride.
ライバルの失敗を聞いて、彼女は小鼻をうごめかした。
Hearing about her rival's failure, she looked triumphant, her nostrils flaring slightly.