Yup, Sa-chan is the one you've heard about with her love of S&M, and not to give spoilers away but, uhhh...birds and bees talk doesn't really happen, since poor Gintoki and Shinpachi just try to make her NOT think about things like that--they get oddly defensive when it comes to her, and I love just how siblings-like they are. It's rather refreshing pace then all the wanna-be sexual tension a lot of other series input whenever it's two teenagers and an old-ish drifter under one roof...I really do think they're a lovely surrogate family to one another...

Oh and ahaha, yeah they all get pumped up for things...really easily in that series...really, really, easy.