Q. Our son, 17, who is generally a credit to us, has started eating with his mouth open. It’s the only thing we don’t love about him. It’s not to do with sinuses and we don’t know if it’s a peer-pressure thing, but when we beg him to stop he always just laughs and insists that: ‘Eating with your mouth shut isn’t a thing any more.’ We are fretting because we have some very fastidious Americans coming to lunch who are important potential clients (and snobs). They are bringing their daughter, also 17, and have specifically asked that our son be there too. Help.

– Name and address withheld

A. Serve food with a pre-masticated texture – for example cheese soufflé, followed by shepherd’s pie, followed by chocolate mousse. If your son has no opportunity to do any chewing and must only swallow, all should go swimmingly.

Q. Last week a great friend who now lives abroad was over in London. We made a plan to go out to lunch at Bellamy’s for a proper catch-up, but when we walked into the restaurant some mutual friends spotted us and insisted we join them. We like these people but it meant we couldn’t have our much-needed tête-à-tête. How could we have extricated ourselves without seeming to snub their kind invitation?

– R.M., London SW11

A. No grudge would have been held had you worn a portentous expression and said words to the effect of: ‘No we really, really mustn’t. Obviously we’d love to but we’ve got to be boring today because we two have something very tedious to discuss. And we can’t even tell you what it is.’ In this way you would have left them intrigued but not offended.

Q. Often if I have had someone to stay for just one night (usually someone who is breaking their car journey between Scotland and the south or vice versa), on leaving they say to me: ‘I have made my bed because you honestly couldn’t tell anyone has slept in the sheets and you can give them to the next person.’ I suspect this is either because they’re too lazy to strip the bed or they’re trying to find a reason not to have to leave a tip for my daily. Actually I wouldn’t dream of letting a bed go unchanged between guests and I resent the suggestion that I might want them to collude in this deception. I never know what to say back to them and wonder if you have an idea?

– T.L., Cockermouth

A. Don’t mention a daily – it could be awkward for them if they are not carrying any cash, as is common today. Just say: ‘Don’t worry. I’ll take the sheets off myself as I never give the same ones to different people.’