Wiktionary
sauce for the goose
prov. A short form of what's sauce for the goose is sauce for the gander
Usage examples of "sauce for the goose".
The reason stood well over six foot in height, and was going to be shown, in vulgar parlance, that what was sauce for the goose could be sauce for the gander as well.
It was on the lines of sauce - sauce for the goose being sauce for the gander, you understand.
What's sauce for the goose definitely isn't sauce for an SSA whose dick is in a wringer.