Q: how can I switch between OS X and windows without setting windows as default?

In OS X, open System Preferences and go to Startup Disk.  Choose whether to start, by default, in Windows or OS X.  Hold down the Option key on startup to choose between them.

I'm not sure if that answers the question?

You can use Alt/Option key during power up of Mac, to choose what you want to start for that specific cycle.

Please also see Boot Camp: Set the default operating system .