Here are three rules for consuming Boston cream donuts in public:
1. Chew with your mouth closed (unless you have shoved half of the donut in your mouth at once in which case just try to cover your face with a napkin).
2. Upon your first bite of the donut, do not exclaim, “Oh yeah, that just happened in my mouth!”
3. Do not moan (although this is usually involuntary, you will freak people out if you run around moaning with a mouth full of donut cream).
If you cannot follow any one of the above-referenced rules, do everyone around you a favor and leave the donut for the experts.