She doesn't seem to realise it at first — but yes

You get up groggily, barely remembering what happened last night. Then it hit you in a rush, and your mind cleared.

Before even putting on clean clothes, you run into the living room where Amy is still sleeping peacefully on her side, on the couch. The blanket you gave her is pulled up to her chin. But it doesn't cover her side, where you can see that at some point during the night, she must have taken off her shirt.

You make an intuitive leap, and realise that she now has DD breasts. A newly precise idea of how big breast-sizes are, and a realisation of what it might mean if she took her shirt off during the night while at your house, makes you quite certain. The question is... what's your move?

You think about pulling away the blanket quickly, but you want to savour the moment. And besides, Amy is still sleeping quite nicely. If she's reacting unconsciously to now being D+ cup, maybe you can take it slow and still have some fun.

You gingerly pull the blanket away from Amy, and are awarded with the sight of her now slightly more generous breasts. Your cock begins to stir.

So does Amy. "Mmmmmmh," she moans slightly.

You figure it is time to put things to the test. "Morning, Amy," you say. "You don't have to get up for a bit, just keep lying there," you tell her. But as you say this, you lift your stiffening member to her lips. Feeling something there, Amy sleepily takes your cock head and squeezes it gently between her lips, licking it. You enjoy the sensation of her lazily tonguing your frenulum, until you decide to gently push in to her mouth.

"Mmmm," Amy moans sleepily. Her tongue slowly strokes against the side of your cock.

You slowly push your erect member in and out of her mouth. But with your excitement, it doesn't take you much longer to come to a peak. "I'm going to come, Amy," you say, a final test before the main event. Amy swirls her tongue over your cock, pushing you over the edge.

You moan loudly as you ejaculate into the mouth of your friend, neighbour, and long-time crush. Amy moans too, but more sleepily than out of excitement. She lazily licks your cock as the last of your semen oozes out of you, moaning with something like sleepy contentment. You stand there in wonder at what you and she have just done, as you cock softens. She never even opened her eyes.

She lets your cock slurp out of her with a soft kiss, and she chuckles sleepily. "Morning, John."

"Do you want a bit more sleep?" you ask her. Ever the obliging host.

"Mmmmm," says Amy, non-committally.

You've satisfied your immediate urge, but you are still enthralled by Amy's breasts, and what it means that they have now become a bit bigger than D-cups. You kneel down in front of the couch, and gently stroke them, playing with her nipples. Amy moans happily, and shifts to lie on her back, as you continue to play with her chest.