This is a comforting gesture, trying to reassure yourself when you don't really believe what you're saying.

这是一种自我安慰的姿势。当你不相信自己在说什么的时候使自己安心。

youdao

He went on saying: "You may don't believe that, the couples went to beach for tanning, because his wife was tanned black too".

他接着说：“你们也许不会相信，他们夫妻俩一起去海滩日光浴，因为他的妻子也被晒黑了。”

youdao

If I can get this information into the back of my head then things don't throw you and you can believe in what you are saying.

BBC: Actor Andy Shields as Inspector Clive Turner in the film