An easy way of making yourself fart is to do a Yoga Pose called the Wind Relieving Pose.
To do the wind relieving pose Lay on your back then pull one knee towards your chest and hold it with both hands. Then gently pull your knees closer to your chest, hold and repeat on the other leg and If possible, you can also do it at the same time two feet simultaneously.
This position will push the gas in the stomach and make yourself fart when bloated.
Walking is also good to help get the gas moving through intestines and can cause you to fart eventually and walking is good for your health as well.
You could also try squatting and forcing the fart to come out which sometimes works for me when I trapped gas in my stomach.