Science fiction sex comedy - it actually makes sense, and this is done very nicely. The vignettes are all well drawn in Foglio's amusing style, and are all gentle and consensual. Some (maybe most) are a little kinky, but there are no dark or hard edges here.
I have trouble calling this erotic, even though every tale (and occasional tail) is 'anatomically explicit.' Foglio's stories are just too comical and cartoonish. The SF angle allows for some otherwise improbable premises, so there are many different angles on mankind's oldest entertainment.
The series is funny, affectionate, and memorable. You may not remember any one story a month later. The happy, funny tone is what's worth a return visit, maybe again and again.