Does anybody know how to stop or lessen a bad snoring habit?

A few options: Snoring can range in severity but it is litterally the sound that air makes through a narrow passage. So widening the passage either through saline rinse or things like breathright may be helpful. Also gravity pulling jaw/tongue backwards is way that it can be worse so try a pillow that forces jaw forward or you to stay off your back when you sleep. Good first steps.

Snoring: Several possibilities: some people only snore if they sleep on their back, so try avoiding that. Losing weight. See an ear nose ; throat specialist to evaluate your tonsils, adenoids and sinus wear a custom made dental device that holds your jaw forward while you sleep thereby increasing the airway.

Not a "habit": Serious snoring is a major health problem. In addition to ruining a marriage, or getting murdered if you're in prison, snoring with cessation of breathing can be sleep apnea -- an important cause of brain damage and sudden death.

Sleep study: Snoring is annoying and may harm your sleep and the sleep of whomever shares your bed or even people in other areas of your home. Snoring can make relationships stressful, but snoring can also be the first sign of sleep apnea, a much more serious health problem. Snoring is considered pathology and sleep study is warranted.