the point is that you log out at top of castle using your dragon and you be with other char log in when you see that you have lose your castle you log in 5 min before is siege end and you can target the pray room of wynern manager too
but you must have little luck to nobody be in pray room this is good when you are only you of clan log in and you must defend your castle alone so you have more % to take it back as you log normal and attack 5 people for example :P