To be honest, there is no real difference between this and full-fledged hentai.
This even has simulated sex and fetish (breast- and foot play), so it's not really suited as "all ages".
But I guess you could call it all ages, given that sexual innuendo isn't usually counted as sexual content (otherwise, a lot of Disney movies would be 16+/18+ age-restricted).
Even then, this is +- borderline on the borderline...
I guess all this confusion stems from the very vague definition of "sex" and "sexual act" since all these liberals and perverts nowadays run sexual act for +- everything that can sexually entertain a human being.
Then again, if we go by the definition of "eros" as sexual attraction, I guess every book that presents the human male with attractive female bodies can be counted as an "ero-hon", even if the female bodies are in undergarments or swim wear(so an all-age "ero-hon" is possible).