Here is the full list of all 100 Busty Hentai Mosaic achievements.
Without outerwear
Outerwear
Koemi, 19
Without underwear, <3
Undressed!
Without a bra
Emi, 20
Akem, 21
Maeko, 20
Utano, 22
Tsubasa, 21
Shiniqua, 19
Nishi, 22
Hisoka, 23
Kana, 19
Mikasa, 20
Rin, 22
Sugi, 24
Tora, 19
Katsuki, 20
This is B
This is U
This is S
This is T
This is Y
Without Outerwear
<3