How My Devoted GF and Sisters Got Turned Into Bitch Gals

Every day is a good day surrounded by your graceful lover, gentle older sister, and tenacious but cute little sister. The only problem is that their hot looks have started attracting other guys.
A buddy of yours shows you Cho-Nukeru!, a dirty website where sleazebags ruin pure young girls in raunchy ways... and who should you see...

* NTR warning

* Is the situation for this kind of harem manga realistic?
It's an unattainably perfect harem manga just for you: the protagonist has a loving girlfriend, a tender older sister and a spoiled, precocious, kawaii little sister.

* There are sharks in the waters of paradise
Bad men who deceive, take by force and denigrate good girls are in this world.
Popped cherry videos, girls grinning as they inspect penis, slut whore play, enticement to old man in adult lingerie, mating party with good looking guy...
the bad men toy with girls to their hearts' content.

* Onward to the main event!
You've got the basics of "a happy life surrounded by pretty girls" and "sleazebags with a porn site". Look forward to the events that follow!
Not for pessimists of the cuckoldry/netorare genre. Now let's get started!