OYC-137 - Shocking footage sent to the failed exam boyfriend

The title is long and descriptive, but it's that 'muddy' orgy work that the studio is good at, right? It's the usual plot where they drink at home and things gradually turn erotic—no explanation needed. As a minor detail, I liked that in the first couple, the girlfriend who gets cuckolded starts participating of her own volition. If I had to ask for more, I wish they had directed her to go from being a 'closet pervert' to showing more uninhibited lewdness.