"to inject me with this stuff"
It's super lame that Washio-soysei somehow remembered all about Julius because of something vague like that.
As for Drako, it's one thing if she was a pro female spy or a succubus getting answers through sexpionage or something, but Drako ain't any of that. It just feels super wrong too since she's a student. Absolutely no pay-off nor satisfaction for the setup whatsoever, and it just made Drako look stupid. But I'll admit, I'll do a lil a chuckle if she's somehow still a virgin because of her tough dragon defense.
Of course, that's assuming Drako actually did all that, and the author wasn't just trolling all of us by dropping a bajillion hints that it happened, but it actually didn't happen.