DS is 15 years old. He's friendly and independent, got himself a paper round at 13, found himself a better job at 14, has worked consistently, is respectful (most of the time), kind, and has a girlfriend he treats well.
Basically, he's a good kid.
But over the past year he has started behaving in SUCH an immature way - belching, farting, messing around constantly.
I could put up with it at home but it has spilled over into school. His school gives 'sanctions' for bad/silly behaviour and he's now getting these regularly.
Before the end of term, I threatened to ground him for a week if he got another sanction. He got one and I grounded him, although I relented a couple of days later as he was so upset about it and sorry. I warned him that another sanction would mean being grounded for a week again.
Today was the first day back at school after the break.
Within an hour he'd got a sanction for messing around again - holding a door shut so his friend couldn't get out of the classroom (nothing malicious - they are good friends - just messing around).
He's just at lunch and messaged me to tell me about it - full of apologies and devastated at the idea of being grounded for a week.
He says all he did was hold a door shut as a joke, and that the sanction - and my grounding him - are harsh.
But I feel I need to stick to my guns to stop this constantly silly behaviour.
Am I being too harsh?