Two weeks ago a group of mums came round to my house on a play date. Jo, a single mum of two, was busy with her littlest one when her eldest, Talia, jumped on top of my child and starting hitting her.
I instantly separated the two and firmly corrected Talia for being too rough. She burst into tears and ran to her mother who was very unimpressed with me.
I suddenly realised that I'd crossed about 1000 lines in those few seconds.
It took a while for Jo and I to get back on an even keel after this incident and I was torn between feeling as if I'd done the right thing, and utterly guilty. I clearly remember my friends' parents correcting me when I was a child but times have changed and it has become something of a minefield.
I asked Diana Mather, managing director of Public Image and a specialist in etiquette and modern manners what the accepted solution was.
"If you are in your own home you have a right to expect other people's children to behave in a civilised manner. If the parents are with you, then ask them to control their child. If not, then you should take the child to one side and try to explain why their behaviour is unacceptable."
Fellow mum Kelly Brake agrees with Diana completely, "If I saw a child acting out of turn, then I would definitely say something to the parents. Children need to know what's acceptable and what isn't. I watch my kids like a hawk in those situations and I would actually be embarrassed if someone came over to me or told my children off."
"I wouldn't mind another parent telling my child off while I'm around," says mum Amanda, "He'll have to get used to other authority figures of varying competence and likeability as he grows up, so the occasional brush with them now is only healthy."
What did become clear as I chatted to Diana and other parents is that 'discipline' does not mean shouting or implementing a punishment. Polite and firm correction is definitely the order of the day.
"When I say 'tell off' I understand it to mean telling them calmly and firmly that their behaviour was not ok," says Amanda, "Punishments, shouting, threats, or other kinds of negative discipline are not my business and I wouldn't want anyone else punishing my child."
"I do reprimand other people's children" says Vicki, "I tread carefully, though, with absolutely no shouting."
However, sometimes shouting does happen, we are only human after all, and a few years ago I did exactly that. When my daughter was only two years old at a softplay centre, an older boy picked her up, smacked her and shoved her down the side of the castle.
I went into complete auto pilot. Within seconds I was by her side and checking her over. She was fine except for a huge bruise on her head. And then I did the unthinkable. I turned and shouted at that boy, "You don't hit other children, that was naughty!"
It wasn't kind and firm. It was definitely a raised voice in anger. To this day I feel utterly horrified by my reaction, he was just a little child, but at the time some instinct took over and all rational thought was left in its wake. I immediately apologised to his mother but the damage was done.
When I ask Sharon Fernandez, founder of www.thebabybook.co.uk, about my reaction she says, "Mums do react like that and they are usually first time mums. I've been in exactly that situation when my child pushed someone! If more people understood that pushing, hitting, kicking, biting and not sharing are all completely normal behaviours, then life would be much less stressful for parents."
Diana adds: "If another child hits or bullies your own in a public place and you don't know the parents, then go up and separate the children. Take the offending child back to the parents. If it happens again, ask the parents to keep their child under control. However, you may have to leave and go elsewhere if things get really out of hand."
I'll be honest, after my experience at the soft play centre I've been extremely reluctant to ever discipline another child.
Still, it does help knowing that a calm, firm voice is an acceptable discipline tool for most parents.
Do you agree? Would you discipline someone else's child or leave it to the parents?