Miss Mary,
As I am a switch as well I an going to post twice. This one is about when I am on the receiving end as that has been the most common mode in the last 15 years.
I will start by saying that in a majority of cases the session has a punishment vibe. This can be explicit in the form of a role play or implicit. There are also sessions where the the vibe is more along the lines of pleasing my mistress' sadism.
My standard spanking is a progression of 4 phases
1] An OTK hand spanking which is a warm up. However if the punishment vibe is particularly strong this step is skipped
2] An OTK spanking with either a hairbrush or very small paddle
3] A strapping while bent over Sometimes the Mistress will mix in some other instruments during this phase Sometimes this phase is skipped
4] The finale which is administered while I am thoroughly restrained This will include canes and heavy paddles and just about anything the mistress feels like using.