Bikini Girl D, a.k.a. "Sports Bikini Top", is one of the members of the Bikini Squad which appears in Episode 2 of Aika R-16: Virgin Mission, Peach Peach Beach. She and her mind controlled friends attack the Treasure Hunting Club under the orders of Risako Nagisa while the unsuspecting girls are trying to have a day of relaxation at the beach. For this offense, they are mercilessly put down by Aika only to be later captured, partially stripped and restrained in the storeroom of the ship.
Bikini Girl D is a slim and athletic looking teenager. She has short blonde hair and fashions a very prominent tan, which is her most distinguishable feature. Like most of her friends, she wears a bikini, which in her case is composed of a low-rise bottom together with a sports top, both grey in colour with black details in the edges. Her beach outfit is completed with a pair of high-heeled sandals.
Overall, she has the look and feel of a proffesional athlete, maybe a beach volleyball player, though this is all speculation since there is no background information to confirm or deny such claims.