FWIW, if you are unfamiliar with Dunkin Donuts, the most common item people buy from there is coffee, by far. In fact, I have seen Dunkin Donuts that only sell coffee.
A lot of their speciality drinks are basically milkshakes though.
Sorry. It's an old John Belushi Saturday Night Live sketch where he wins some Olympic-type events and then the voiceover claims that "little chocolate donuts" were part of his training regimen. Last shot is a picture of some fat, stubby fingers holding a half-smoked cigarette and reaching for another donut.
A lot of their speciality drinks are basically milkshakes though.