Why Should You Wear a Slip?

From: Couture Allure Vintage Fashion: Why Should You Wear a Slip?

Interesting to me:

Fact is, you shouldn't wear all those controlling foundations without a slip between them and your dress. A slip will slide over your bra and girdle and provide a smooth layer over them. A slip will keep your dress from catching on the edges of your foundations. A slip will keep your dress from clinging or riding up in unattractive ways.

The question I have, for me, is when I wear a girdle to work (usually open bottom), since I'm wearing it under a suit. Is a slip needed?

I'd argue, yes. Obviously, not a full slip, but something to provide a smooth layer over the foundation garment. I think in that circumstance, either a full pant slip (kind of warm in the summer), or tap panties, do the job.

That's my solution: Full cut panties under the girdle, then the girdle, then a pant slip or tap panties.

Thoughts?