“My parent-in-laws’ behaviour makes me cringe. I don't know how to tell them to stop it."

It’s great when grandparents and kids have a playful physical relationship. But what happens when a grandparent touches a kid in a way that the parent doesn’t like?

This is the problem faced by a mum on UK parenting forum Mumsnet.

She has a three-year-old son, and her parents-in-law have a habit of playfully slapping her son on the bum every time they see him – up to 20 times in a visit.

“He can just be running around or playing and father-in-law just randomly slaps him on the bum, or if he’s climbing up onto the sofa, mother-in-law will start slapping his bum,” a user calling herself Blanchethegreat wrote.

“Just to be clear, I’m not accusing them of anything untoward. I know that babies’ and even toddlers’ bums are cute and of course I’ve patted my baby’s bum in an affectionate way when cuddling him, but they’re not his parents, he’s getting older now and I don’t like the way they do it repeatedly and randomly.

“They’re not hurting him and they are only playing around but I absolutely f–king hate it. It makes me cringe more and more as he gets older and I don’t know how to tell them to stop it without offending them.”

People who responded were split. Some told her she was overreacting.

“My two granddaughters are seven and almost four,” one woman wrote.

“Occasionally I pat them on the bottom – nothing sinister or wrong in that, just playing. They do it to me too, sometimes. I think all this over-analysing every single action in case it can be the sign of something inappropriate is mad.”

“Oh, how things have changed, and not always for the best,” another added.

“Younger mums are now worrying about things that were the norm previously. Grandparents patting bottoms is really nothing to get yourself in a tizzy over.”

Mamamia staff share the worst thing their in-laws have done. Post continues after video.

But others felt she should put a stop to it.

“Looks dodgy to me,” wrote one person. “You need to be more assertive when it comes to your kids! My father-in-law insisted on kissing my six-year-old son on the lips. I made sure he stopped.”

“In the old days children were not allowed feelings, only adults,” added another. “I would definitely say something because your silence is showing that you also don’t think children should have feelings.”

Another said she didn’t think it was done with bad intent. “But I don’t think it’s appropriate,” she adds. “What is he does start copying and keeps hitting other children? Or others?”

I can understand where this woman is coming from. You get family members and friends who have a different idea of what “playful” is when it comes to your kids. Maybe their idea of roughhousing is rougher than you’d like. It’s hard to say something when it’s someone close, because you don’t want to hurt their feelings.

But ultimately, as the parent, you have the right to set the rules. And if this woman is uncomfortable, she should speak up and make the bum slapping stop.

What would you do if you were in this situation? Tell us in the comments section below.