His mother complains that he makes excuses to chicken out of family occasions such as weddings. [VERB PREP. + of]

他妈妈抱怨他找借口躲避家庭聚会，如婚礼之类的。

I had never ridden on a motorcycle before. But it was too late to chicken out.

那以前我从没骑过摩托车。不过，想退缩已经来不及了。