: They have been friends since childhood and are both extremely introverted ("incha").
: Sazu acts as a catalyst for the couple's development. She and her friends provide "sex training" to help the introverted pair overcome their hesitation. OVA Incha Couple Ga You Gal-tachi To Sex Traini...
Characters like Sumire and Momo provide the social and physical contrast to Suzune's introversion. : They have been friends since childhood and
If you meant (Inuyasha & Kagome), here are useful academic-style papers and resources: OVA Incha Couple Ga You Gal-tachi To Sex Traini...