You often don't know you're happy until it stops. But this can be overcome. By buzzing, you can enjoy those times when you are happy, and (with practise) edge yourself out of darker moods.
Start on a day when you're feeling OK. You don't have to feel great, just wait until you're not down or stressed or tired. Sit down somewhere comfortable and relax
Smile. Just a small smile. And imagine something that makes you happy. Something cute - a favourite small child or a basket of puppies. Feel the smile it brings to your lips. And pay attention to the rest of your body: what does that feel like? Do you feel a tingling sensation anywhere: perhaps in your finger or toes, or maybe in your cheeks? Pay attention to that feeling. Enjoy it. And begin to smile more. Paying more and more attention to the buzzing, tingling feeling. Feel that feeling move and grow.
Now smile even more. A big smile - a smile anyone looking at you would find ridiculous. Have fun with it - gurn with all your heart. All the time, pay attention to your body - pay attention to haw smiling and feeling happy feels.
Now hold onto it, and enjoy it for as long as you can.
This is buzzing. With practise you can do it, not only in a comfortable chair, but while waiting for a bus, or while walking along the road. Buzzing can even lift you out of a bad mood (sometimes), and when you're in a good mood, boy do you notice it more.