Characters are shown in swimsuits, and bathing but it's really hard to perceive this as sexual

A character trips and falls and it's implied that their panties are shown to The Whole school. The actual shot isn't shown(a blue and white striped rice bowl is used as an implication). The characters (mainly Ristu) sometimes mention it as a joke to get Mio freaked out

One girl is a fan of yuri (lesbian romance) she blushes sometimes when she sees two girls in situations that could be perceived as romantic.

a few boob jokes, one of which uses a close-up of Mio's breasts, teacher is a pervert

in S2 Ep1 Ritsu looks at a girl's chest and says "You Haven't changed at all from last year"

To tease Mio, Ritsu often talks about scary and sometimes disturbing things, but since the show is very light hearted, it's not scary or disturbing in the slightest and is more used as a joke

Mio hits Ritsu a lot for comedic effect

Bloody noses are shown sometimes.

Crap, Stupid and words like that are used sometimes

The official dub has some mild swearing. Hell, damn, ect.

b@$@rd and @$$ are said in season 2 episode 10

Absolutely Nothing!

Teacher is shown drunk but not drinking

Nothing about this anime is intense or frightening.