DS(4) off school with "tummy ache" and I'm feeling played

[Anticyclone]

DS1(4) is in reception and has been struggling with the return to school after the Xmas break. He was tearful on the first day before and during school, and on the second. I know this is totally normal and it doesn't help that he is one of the youngest either.

This morning he was moaning and writhing around saying he had a tummy ache, and I've given him the benefit of the doubt and let him stay at home. But I've forced him to stay in his room, in bed, with no toys or books to try and make it as boring as possible. But of course now he seems totally fine and I'm pissed off as now I'm missing my only regular (weekly) playgroup with DS2.

I really don't want this to become a "thing", what do I need to do to make sure he doesn't try and pull this stunt again?

Yeah you’re setting a bad trend of plonking the kid in front of the tv in a nest when he’s lying about being ill because he doesn’t want to go back to school.

My DC have never (yet) faked illness in order to avoid school. They're age 6 and 9 and have maybe 3 or 4 days off school a year on average, for things like high temperatures or tummy bugs.

Maybe as they get older they'll want to be alone in bed when ill, but for now I prefer to be able to keep an eye on them (whilst going about my work/housework) and for them to feel comfortable and cared for. If really ill they sleep on and off on the sofa. Otherwise, watching TV is a pleasant distraction for them.

My DD (also 4) did this for a while at nursery and school. DH and I both work, so can only take a day off for genuine sickness. We always send her in if there's no fever and no vomiting, with the promise that we will pick her up if needed.
It's always anxiety with DD, and I sympathise with that, I really do. But I also know that avoiding school will only make the anxiety about going worse. Since the October half term she has not once complained of stomach ache. She's settled in and made friends so isn't as anxious any more.
To start with I really questioned if I was doing the right thing by not keeping her home.