[T.L.]

Hi I'm looking for an old manga that I found on the site a few years back.
In it a group of class mates are getting ready for a trip to the beach, but they need one more person to go for some reason.
They pick a mousey looking girl with a (Seemly) flat chest, but she is reluctant to go, so they then turn to her old childhood friend who is also going to talk to her and convince her to go.

Well the boy go's to the girls house to ask her way she doesn?t want to go, because as it turns out she used to love to go swimming. Well the reason way is because well he Bust has gotten so big that it requires more than one zip code.
(That's an exaggeration, but they still pretty big.) In accordance with character type she very embarrassed by this, and very angry with him. She blames him for current predicament.
(He used to grope her when they were kids. Jokingly saying it would make her chest grow.)
This being a hentai I think we all know what happens after that.

So does anyone remember this and/or have it?