Well, among the problems of the traditional neck-suck is that you pretty much either drink from the carotid artery, which is high pressure and tricky to stop, or from the jugular vein, which will be carrying oxygen-depleted blood with various brain waste products in.
Drinking from the breast, on the other hand, gets you fresh blood at a lower pressure close to the heart, and makes it easier to heal (assuming you're wanting to keep your drinkee around for later). And as a plus, the capillaries will be filtering through the fatty breast tissue, giving you a richer, creamier mouth-feel.
It's all pleasantly medical which makes me think think the Med Student theory, and then the last sentence just kinda throws the whole thing into suspicion.
The vampires! They are among us!
What are you talking about, Medusa?...yes, sister.Sucking bloodIn other words, hurry up and expose your chest, Medusa!Eeeh?!!If it's just sucking blood, there's no need to take off my clothes...You really are always the same useless Medusa, huh?The Type-Moon style is to suck blood from the chest!Well then, Medusa, once again we're going to suck your blood as punishment!Eeeh, that's?!?It's the first time I hear that, sister.