Bend your head downwards
If you are about to laugh, you must bend your head downwards to ensure that the person in front of you does not see your face. If your hairs are long, you can use them to hide your face. Note that after bending your head downwards, you should not try to look into somebody’s eyes and keep looking on the floor to hide your expressions. Allowing the other person to see your face will not good to you as your expressions will be exposed and they will know that you are going to laugh.
Slip your tongue between your lips
In order to hide your smile, you must slip your tongue between your lips and stick it to the upper lips. This way you will be able to control your expressions and control your voice as well. Remember that, in order to laugh on the inside, you must not open your mouth. It is necessary that you use your nose for inhaling and exhaling oxygen.
Control your breath
This is the most vital part for laughing on the inside. You should control your breath and grasp it for a while and this way you will be able to control your sound. This will also assist you in laughing on the inside as a clicking sound will be produced in your body. Not to mention that only you will be able to hear that sound and others will be unaware of it.
Do not allow any voice to escape
You must have full control over your voice and do not allow it to escape. For this, inhaling and exhaling slowly will help you a lot.
You can also turn a little backwards to conceal your expressions and if you find an opportunity, then walk away from the person.