How to prevent your onii-chan from looking up other girls' skirts: 1. Be tsundere as fuck to assert dominance 2. Have sex with onii-chan 3. Repeat step 2 all day everyday 4. ??? 5. Profit
So these chicks want our protagonist to take over a shrine and become a prist. He says he ain't interested. They propose a radical idea. How about he just impregnate them, and his kid can take over the shrine when he grows up! Why of course!