DD is 17. She's in her room with some pals and I could hear a noise which sounded like gas being released (like when you fill your tires with air) and laughing. Suddenly it dawned on me that it must be laughing gas. I don't want to cause a scene for DD so texted her and asked her if it is and she said yes. I asked her to stop or I'll ask her friends to leave. She insists it's not as bad as alcohol. They've finished the canister anyway so it's a bit moot now but...
This laughing gas thing is completely new to me. Would you allow your DC to use it at home? Aware that she'll use it outside anyway whatever I say and safer to be at home (we are not in UK and live in Asia) but also don't want to appear to be approving of this!