Harem Mate

The protagonist (player) is a new manager at a production agency for five heroines. One of them, Akiha Jyujyu, is his childhood friend (she calls him 'Onii-chan'), and her mother is the agency's boss. Another, Saeki Azusa, is his former underclassman (she calls him 'Senpai'). The other three are strangers. After H scenes with two heroines, the remaining three discover that having sex with the protagonist inexplicably boosts their luck in getting job offers—actual sex helps more than foreplay. The word spreads, and the rest also sleep with him. The story follows the heroines deciding to continue this arrangement for luck, though the two who knew him already have feelings. This sets the stage for free H mode.