Whole milk is actually only 3% milk fat. But yes, it will work for some applications. I steep my used Volcano bags in milk and enjoy the effects all the time. Now, that said, that is vapor resin. Steeping MJ by itself, or ABV, I don't think there would be enough fat to assist in the release of the psychoactive ingredients. You might be better off making the MJ into butter, then use that butter to make homemade chocolate, and make your own hot chocolate from that. Time consuming? Absolutely. But you'll see far better results.