What is the best stomach exercise to relieve bloating sensation?

CV and Core . Core strength exercises can help improve tone in the abdominal muscles. This can be combined with cardiovascular exercise to improve the shape of your abdominal muscles. I prefer core exercises that occur in lengthened positions such as plank position, sit backs and standing movements. The rule is to start slow and be persistent. Don't rush it and you will see changes over time.
None really. A bloating sensation, if it's due to abdominal obesity will feel better with weight loss, but you can't spot reduce your belly by just doing abdominal exercises. Given all that, it's unlikely the bloating is due to this, you need to get thoroughly checked out by a doctor to determine the cause.