Hm.. laughing during serious situations might be very inappropriate at times but I get understand why one sometimes find certain solemn situations funny. Our sense of humor might be a tad off at times.

• Well, for me at least, I managed to suppress laughter using these few ways:

1. I disengage myself from the situation at hand and think of all the things that are really sad and depressing to me, things that almost made me want to cry. They certainly help quell any thoughts of laughing although they also make me feel upset.
2. Think of a mathematical equation, something that is complicated. Like 0.9×5×8+4/8 (you get what I mean). The point of this is that I find myself distracted from whatever I felt funny at the moment when I am trying to solve the mathematical equation. If it does not work for you, distract yourself with something else like any problem that requires you to think hard to solve.
3. Try to come up with reasons why the situation is not funny. Think of things that make you uncomfortable in the situation. For example, it is too hot in here. You want to sleep but have to listen. You dislike the topic that revolves around the situation. You wish the person that you dislike is not here. Oh, you might feel yourself getting more and more grumpy with each complaints but it sure helps in supressing laughter.