If you've seen the main series, you know what to expect from the specials. They're all short, just over one-minute long streams of consciousness that mainly boil down to lesbian breasts rubbing against other lesbian breasts. Because each episode is so short, I'll just give quick reviews for each one.
Special 1: Standard yuri scene between Mamori and Mirei. Some dialogue thrown in as window dressing to bookend it, with orgasms galore for the rest of it.
Special 2: Charlotte in the bath fantasizing about all the different girls she can have S&M fun with. Special mention goes to her getting so aroused that her nipples pop
out from their inverted state.
Special 3: A solo-session with Kasumi, who spends most of the special imagining having sex with Hibike. Ends with an orgasm and some tears in an attempt to pretend it's deeper than it is.
Special 4: Another solo, this time with Akira. Basically a two minute-long monologue of how she misses her partner and woes having to pretend to be a man. How exactly she's able to compress her massive breasts to such a flat state without obvious overhang is never revealed.
Special 5: Probably the most extreme scene out of the bunch, featuring Rei and Lady J going to town on each other. Stand-out scene involves an intense finger-fucking of J's nipples.
Special 6: Momoka fantasy centering around her playing with Mirei's breasts, ending with her snapping out of it while playing with her own.
In summary, the specials are exactly what you'd expect from a series like this: Small, previously unseen ecchi highlights with even less real plot to speak of. Watch if you're out of real hentai.