To make the entire room a casting cirlce.
Stand in the centre of the room point your wand at each wall one at a time saying:-
" This wall is a protective shield, within this room is a positive field "
Then say ( spin while saying this ):-
" This room keeps us safe within, noharm can enter or remain in. This room will enhance every spell, ensuring that it is cast well "
Trace a pentacle in the north, east, south and west.
:: This is very helpful when you are casting a spell/ ritual that involves moving/dancing. It also good for people that find it really hard NOT to step out of the circle. ::