So Noel was in a case of breast envy becasue she was surrounded by Big Breasted beauties like Mai, Dizzy, etc. and in her frustration she had all these weird fantasies in the form of a big ass orgy with all the girls, then when she finally returned her own dimension/world she finds what.... That She's STILL surrounded by Big Breasted Beauties like Litchy and Makoto. Guess what is next?
For the record, Noel is in her 20's (according to Wikipedia) and I think her chest size is normal for someone her age. The only reason she's self-conscious about it is because of her days at the NOL Academy, where some people liked to make fun of her for it. That just escalated because of people like Litchi, and Taokaka's nickname for her, "Lacking Lady", isn't helping her get over her trauma.