how to unlock 3 girls church?

[MeowMoew]

tip said need be in heat but how? already fill up their desire

[Traitor]

When you hit like stage 6 or 7 of the Common route it will explain the "In Heat" status. Fill up their desire bar the day before they are at the church. Mon/Tues is the older sister, Wed/Thur is the blonde, Fri/Sat is the blue haired one. Then go to the church in the afternoon and you will see an event. You can do them back to back to get both events one after another, just need to fill up the appropriate girls bar the day before.