Synopsis:

Protagonist Satoshi is a working student who goes to university by the scholarship. Though it becomes a manager in the apartment, residents there were only elder sisters. Moreover to Ibaraki appears the introduces self calling zashikiwarashi(room child) when the clock tower in the apartment is repaired, the way things are going black aura of residents will cause big unhappiness after half a year, in addition all the black auras that loses the place will fall to Satoshi, it is said that the poverty-stricken life is waiting hereafter.

Pour the positive mind that mixed power of Satoshi and Ibaraki into residents to evade the accident.
In a word, it has sex and positive aura <> semen is "Inside ejaculation".