I love drinking warm milk w/ honey before i sleep. i do a detailed cleaning right after but even w/ brushing, can it cause cavity? i now use a straw

Hmmm: The chance of causing cavities is directly proportional to the amount of time the sugar (& milk) is in contact with your teeth. Therefore, sipping it over a long period of time is bad. Drinking it (with\without a straw) over a short period of time followed by rinsing (brushing & flossing) minimizes the chance of cavities. My recommendation- have your own dentist evaluate the health of your teeth.

Cavity risk can vary: Some people can do that their whole life and not raise their risk for cavities. What we do know today is that there are factors you can't control and some you can. The obviously controllable factors are what you eat and how often, and how well you clean. If you had a lot of cavities as a kid you could be increasing your risk by doing this. If not then it may be okay. Dentist can assess your risk.

Not recommended: Plaque can build and bacteria can thrive between your back teeth, producing the acid that destroys tooth enamel and cause cavity.

Yes, and more: Bacteria thrive in warm moist environments. Bacteria can take sugars from both the milk and the honey, converting the sugars into harmful acids. Please make sure to floss as well as brush, and a fluoride rinse may be wise. It is also recommended, for weight control, to not eat or drink within two hours of going to sleep.