There's a frequent gag in the series when Mikoto buries or grabs Mai's breasts

Some innocent nudity, when characters take baths. Nothing graphic

There's an episode when all the girls' underwear are stolen, which is very comical

Natsuki is accidentally exposed, revealing she isn't wearing underwear under her skirt. You see her pelvic region before she quickly covers herself and brutally blushes. Later she explains that someone or something stole her underwear (along with other girls')

There's some cleavage in the show. Meant for fanservice

Some violence throughout the series, though nothing graphic; however blood is show a few times

Some of the himes are seen fighting monsters (called Orphans), and later it is revealed that the himes have to fight each other

Not very much swearing. Some words used like hell and damn

A school nurse and a (substitute) teacher can be seen drinking (and getting drunk) on various occasions