Ah! Well! Since you put it THAT way, maybe I can dust off my old Captain Chivalry costume ...
All right ... I'm your doctor, and you're in my office, and I inform you that it seems that you have special breasts, that they contain not only mammary tissue but special air sacs, and they appear to provide extra air filtration for your lungs. We've never seen them in real action before, so now I want you -- in the interests of science, you understand -- to put on this oxygen mask and breathe extra deep, try to take in more air than you ever dared before ... go ahead, breathe dee-eep ... yes, there is a slight extra rise and fall, a fluctuation in breast size; keep inhaling, that's the way ... yes, your breasts are now slowly but very nicely expanding ... very nice expansion, yes, very, very nice ... a little bit of a wobble to them, as if theuy were helium balloons ... allow me to just quickly check the texture ... interesting, light and very wobbly like ballons, but a nice full texture, firm like foam rubber yet a bit squishy like a nice tasty chocolate pudding ... all right, I'm realeasing the breasts ... yes, we're talking about a major cup size now, at least an F ... and we're rising up into that stratosphere occupied by exotic dancers ... damnation, you would make a decent contender in a strip club now ... look at the nice, snug, tight cleavage that your tits -- that your mammary glands are forming ... why don't we, um, test your to your, ah, fullest capacity, just to be sure what exactly we're dealing with ... my word, your capacity for expansion is remarkable. Have you ever borne children? because your skin is stretching and conforming to this radical new demands very nicely and easily indeed, its quite phenomenal really ... yes, ah, you're in the higher class of the large-busted strippers ... each breast is practically the same volume as your head ... How do you feel? Oh, you feel incredibly sensitive, interesting ... yes, I gather from the way you're swirling your outstretched hands over your fat outthrust nipples and your expanded areolae that you are receiving magnified pleasure from such an accentuated bust sixe ... I see you shutting your eyes, licking your lips, then chewing a little on your lower lip ... what's that? You're coming up on a nipple orgasm, you say? And so quickly too! I must say, that you are generally acting ... VERY heated up and horny, you've got your hands all over yourself ... your breasts are expanding even bigger ... I think it only fair to warn you, you may well become one of the bustiest women of which there is any reliable record, a true giant among women ... you want to keep going? Ah, well ... far be it for me to disagree with a patient; yes, by all means, let's keep ... going ...
Perhaps something like that.