How do I control myself if someone serious is talking to me?

When someone starts talking to me with a serious face I always start laughing. Once someone was talking to me and I had to run to the bathroom to explode lol. How do I control it?How do I control myself if someone serious is talking to me?
just imagine them doing a wheeley on a unicycle riding through an oil refinery juggling flaming chainsaws.How do I control myself if someone serious is talking to me?
When I find myself barely containing laughter at inappropriate, serious moments, I try to think of some of the saddest things and times I have experienced. This often helps me contain my laughter by bringing back those sad emotions.
i'm assuming you mean this is just a reaction you have and not you being silly so what i'd try is finding something that doesn't make you laugh and focus on it. i think its just that you're nervous.
its just nervousness and self esteem have more confidence in yourself and start thinking of a response and get into the conversation
When There talking start thinking of something else but still be in contact with the other conversation or what i do is start pinching myself i soon stop laughing
Just don't think about anything funny and see where the person is coming from.