stiff upper lip

[sumo]

I've already checked some dictionaries but can't get it clearly.

http://www.usingenglish.com/referenc...upper+lip.html

Is this expression only for bad luck?
I think I heard someone said he had to keep a stiff upper lip when he really wanted to laugh in a serious meeting.

Would you use this when you hold your laughter?

[BobK]

I've already checked some dictionaries but can't get it clearly.

http://www.usingenglish.com/referenc...upper+lip.html

Is this expression only for bad luck?
I think I heard someone said he had to keep a stiff upper lip when he really wanted to laugh in a serious meeting.

Would you use this when you hold your laughter?

Not really. The expression "keep a straight face" would be more appropriate. Here are some other 'restraint' idioms/collocations:

sit on one's hands [i.e. don't applaud] - show no approval
bite one's tongue - not say something that one really wants to say
stifle a yawn/giggle/sneeze - not show boredom/laughter/sneeze

b