Follow these suggestions for naming your parents-in-law.
Come right out and ask your mother-in-law and father-in-law what they want to be called. I know, I'm suggesting something radical here, like eating less if you want to lose weight or not baking in the sun if you don't want skin cancer.
People in second marriages often feel more comfortable calling their parents-in-law by their first names rather than as "Mom" or "Dad."
Talking about the name issue right up front allows everyone to air their feelings and knocks stress down to manageable levels. But talking about something that's as loaded as a frat boy on Saturday night is easier said than done. Hey, I've been there and, I'm ashamed to say, not done that. So
Follow the lead of the rest of the family. Obviously, this is only going to work if there's another daughter-in-law or son-in-law and the issue of names has already been settled to everyone's satisfaction. With the name game, one size does not fit all, so you have to be mighty careful you don't get sucked into calling your parents-in-law something that doesn't fit in your comfort zone.
If you're the first to get married, there's no lead to follow. As the head weenie at the roast, you have to blaze new ground. In that case, see suggestion #1.
Use their first names. My sister has a delightful mother-in-law, a lively and intelligent woman whose company I greatly enjoy. Her first name is Mera, and that's what my sister calls her. It works for them.
Invent a name. Sometimes you're just not comfortable using your parent-in-law's first name, even if that's what they have indicated they want you to call them. In this case, you might want to consider inventing a name for your parent-in-law. Of course, the name must be mutually agreeable to all parties.
For example, my mother's first name is Erna. For some reason that I can no longer remember (if there ever was a reason in the first place), my husband and several other sons-in-law call my mother "Oin," a mangled variation of Erna. She appears to like it because it's special and sets her apart from all the other Ernas in the world. All two of them.
We've done the same thing for my father-in-law. His name is Louis, but everyone calls him by his middle name, Nick, which he prefers. I don't call him by either name. Instead, we made up the name Nas, the first part of a juicy Greek curse he uses to amuse us. The first few words of this useful imprecation are "Nas a fahn a..." (Here's the entire curse in translation, in case you ever need it: "May the red goats eat out your stomach lining and the white mice, too.") So my father-in-law has become Old Nas; my husband, Young Nas. Again, he likes it because it's as special as he is.