While I do feel bad for Ruka, I just can't agree with her methods.
Also another gripe I have with manga protagonists, why doesn't he just either avoid the kiss or stop it just after it starts? It's not that hard to do, if you get this flustered by as kiss at 20 years of age you should take a good look at yourself. Even more so since he already decided that he cannot be with her, one of the reasons being that she is a minor. It doesn't take effort to reject a minor's kiss, all you have to do is want to reject it
Also another gripe I have with manga protagonists, why doesn't he just either avoid the kiss or stop it just after it starts? It's not that hard to do, if you get this flustered by as kiss at 20 years of age you should take a good look at yourself. Even more so since he already decided that he cannot be with her, one of the reasons being that she is a minor. It doesn't take effort to reject a minor's kiss, all you have to do is want to reject it