Wow it seems to me there's been a big duscussion here about engolir o sapo X bite your tongue
I must say I did little research on some good and apparently reliable websites.
One of the definitions I found that really struck me was
Bite Your Tongue ( keep yourself from speaking ... )
"bite your tongue"
You "bite your tongue" to keep yourself quiet and not say what you want to say. Example: "I wanted to tell her what I really thought of her dress, but I just bit my tongue." It is not always right to speak out and express what comes to mind; at times you should bite your tongue and keep quiet. Example: "Whenever that professor says something I don't like, I have to bite my tongue." When you really want to speak out, but you know you should not, it is best to just bite your tongue. Example: "Just as the coach started yelling, he slipped and fell. We all had to bite our tongues to keep from laughing." http://www.goenglish.com/BiteYourTongue.asp
Hope I'm lot late so thought maybe I could suggest another idiom which in my opinion perfectly conveys the engolir o sapo idea.
Take it on the chin
Definition: to be brave and not to complain when bad things happen to you or people criticize you