Does anyone know what's the name of this manga? I read it last year but can't find it now :(

Apparently, there were a priest and his kohai. They were exiled (or fled?) to earth from heaven(?). After several years, they tried to return to their world, but it was occupied by demons. So they seduced these demons to have sex with them so that the demon's weak points would be exposed (?) and could be easily killed.