[avalaunch]

Except sometimes your silence will be used against you:

http://www.npr.org/2014/10/05/353893046/you-have-the-right-t...

http://www.slate.com/articles/news_and_politics/jurisprudenc...

[ikeboy]

You need to say "I am exercising my right to remain silent", then shut up.

[avalaunch]

And based on the second article I posted, you also need to make sure you don't look uncomfortable while stating that you are exercising your right to remain silent.