To the one, it seems easy enough: If the series has an ecchi tag associated with it, one is best advised to simply avoid it. In truth, it is not so much a prudish rejection of sexual stimuli in animated motion media, but, rather, a critique disdaining the waste of prudery. The tropes are myriad and obvious, with the result that it really does seem childish to a creepy degree. Say what we will about the (ahem!) “premature nosebleed”, but it does kind of work as a catch-all symbol within the frame.
More problematic, of course, is the blatancy of the stimuli. It is almost hilarious when baseball and anime overlap off-screen, because those who will discuss in earnest the physics of a left-handed pitcher’s throwing motion in relation to the placement of the heart within the human body apparently find no reason to wonder how this or that best fighter in the Universe managed to pull off that maneuver without slicing off one of her myth-cupped breasts.
The nature of ecchi, though, is to not be so explicit as, say, hentai or open pornography. But the artists do seem to revel in what they do present. And it is, of course, one thing to chuckle at the outsized breasts popping into open air, and the goofy sound effect that goes with it, but somebody had to draw that.