Tsukitokage tends to do some great Vanilla, so I'm happy to see more.
'This is all for science', eh? Sounds great. Seems like quite a great invention though, except I think in a Hentai world it's kind of...not really needed?
Great ending. Well, certainly I see no problem with just using it between the both of them...Heck since she was talking about declining birth rates, why don't they get married and have children? That way they're contributing to lessen declining birth rates, sort of.