Dear Miss Manners: I had a group of co-workers over for dinner, and one of the women brought a delicious chocolate cake for dessert. As we were finishing dessert, a neighbor dropped over.

She sat down at the dinner table, and I poured her a glass of wine. She reached over and took a piece of candy that was sitting on top of the cake — and I was okay with that, as her fingers touched only what she was eating. Then she took some frosting off the cake with her finger. I think she saw my eyebrow raise, as she then went and got a spoon.

Knowing she can't eat gluten, I did not offer her a piece of cake, but she kept using the spoon to eat the frosting. You get the picture: Spoon in the frosting, spoon in the mouth. Spoon in the frosting, spoon in the mouth. She ate almost all the frosting off the remaining half of the cake.

I ended up throwing away the rest of the cake, as I didn't want anyone catching a cold if she had one, and who wants cake with just a little frosting?

I know what she did was wrong. What I don't know is how I could have politely said to stop. How do you say, "No one else is going to want a piece if you take all the frosting — especially when you lick the spoon and put it back on the cake"? Yuck!

I didn’t want to make a scene and embarrass her. My other guests were silent, but I think they were as puzzled as I was. How do you stop that behavior politely?

Some problems — like avoiding oncoming trains — can best be solved with quick, decisive action. Smile; say, “The frosting really is delicious, isn’t it?” and follow it with “Let me help you with that.”

Then take the cake away. In the kitchen, cut off as much frosting as you can spare, put it on a separate plate, and set the plate before your unsanitary guest. (The cake itself can be left in the kitchen or moved to a more distant part of the table.)

This will allow you to save some of the cake while appearing to be the good host/hostess. And as an added bonus, Miss Manners assures you of the admiration of your other guests, who were no doubt feeling the same revulsion as yourself.

Dear Miss Manners: I have a friend who hooked up with a woman he met at a local club. Come to find out, this woman knows his mother on a professional level. Is it okay to have a relationship with this person? Just wondering.

If your friend has no objection to his girlfriend being in business with his mother, Miss Manners sees no reason to protest. Whether his mother will is another question.

Dear Miss Manners: What is the proper response to my guests who ask me what they should bring to my table?

“The pleasure of your company.”

New Miss Manners columns are posted Monday through Saturday on washingtonpost.com/advice. You can send questions to Miss Manners at her website, missmanners.com. You can also follow her @RealMissManners.

2021, by Judith Martin