I think you guys are setting yourselves up for disappointment. Junichi already said he almost exploded just from her touching him in the bath, you really think he'll last long enough to do the deed when he has to actually stick it in?
He's going to blow his load prematurely and it'll kill the mood and she'll comfort him before saying they'll go farther "next time" then he'll get dragged away on another whirlwind plot by the other side characters and she gets shoved back onto the bus the author loves to put her on.