More like a George Feydeau farce than a 1930's Hollywood screwball comedy, "Getting Gertie's Garter" is a small budget film with plenty of laughs. Constrained by the censors of the time (1945), it still manages to do enough "couple swapping" to qualify as a sex farce. But be warned, to really enjoy this film you have to throw all logic away.
The "small star" cast of Dennis O'Keefe, Marie "The Body" McDonald, Barry Sullivan, etc. are not the most famous of Hollywood actors. Still they manage to set the right tone and pull it off.
A silly piece of fluff that runs only 72 minutes, "Getting Gertie's Garter" like "The Horn Blows At Midnight" (1945) and "The Boys from Syracuse" (1940) is a mostly overlooked gem. If you are into comedy, it is a must see.