The satisfaction registered by their smiles was priceless. They were brothers in arms surpassing their parents in the courage stakes, taking Dreamworld's Buzzsaw ride easily in their stride.
We watched from the ground, relieved we were not the ones being turned upside-down, sideways, reversed and stopped halfway up the steepest slope. We were looking forward to the more sedate Thunder River Rapid ride.
It's all good family bonding stuff at the Gold Coast, a holiday destination that works well for teenagers and their parents.
When we pitched the idea of a week away to our 18-year-old before he flew the family nest, his first suggestion was Hawaii. Sorry, that was a no. Too far for one week, too expensive and he has the rest of his life to travel - something closer to home, please.
The Gold Coast received everyone's vote. It's close, we've got family living there and the 18-year-old was keen to catch up with a mate in Brisbane.
Along with its amusement parks (Dreamworld, Sea World, Movie World) we also love the beaches, walks and cycling lanes, and how on early morning promenades we (the parents) can watch surfing lessons and tai-chi groups before stopping at one of many cafes for a caffeine fix before returning to our hotel room to rouse the sleeping teens.
Travelling in the school holidays, we were deprived of those ultra-cheap fares and deals. But what the hell, we were on holiday so we booked three nights on the Coast, one night in Brisbane and family time with my sister south of the border.
We assigned booking accommodation to our 15-year-old - must-haves were being near the sea, free Wi-Fi, a pool and gym. After a few false starts (fantastic properties but double our nightly budget) he found the Meriton apartment deal.
He picked a winner: indoor and outdoor pools, spas, billiards room, laundry, gym and 99sq m to spread out in with kitchen, lounge, deck, two bedrooms and two bathrooms. Beach views from the 10th floor, too.
After a 5am check-in for an 8am landing, we caught up with the family before driving to our Broadbeach base.
I curse that youth-culture television show The GC, as our teens have that hedonistic idea of the Gold Coast implanted in their brains. I think some of the people on the show are dicks but the teens reckon they're "rich dicks" and they'd love to try out the GC clubs if they could.
The first day was rainy so we saved the theme parks for the forecast finer days, and set our Google Maps apps on our iPhones (with an Aussie SIM card) to navigate us to Harbour Town, a discount shopping centre north of Surfers Beach - great for sourcing teenagers' favourite brands at affordable prices.
The centre's tourist lounge gave us a discount card; we were happy shoppers, catching a new-release movie and finding a cafe serving teenage-sized portions.
The next days were dedicated to thrill-seeking. At Movie World, our plan to start with gentler rides was ditched when the line for the Green Lantern was unbelievably short.
"My, Mum, you sure can scream," was the 15-year-old's verdict as we came to a stop, my eyes shut all the way.
Unfortunately, Superman Escape was undergoing super-maintenance but the Arkham Asylum and Scooby Doo roller-coasters were other challenging options. We also enjoyed the 4D theatre, the Wild West Falls Adventure Park and giggled at Austin Powers and the muscle-flexing superheroes posing with fans.
We finished the day at the neighbouring Wet'n'Wild Water World, where the teens got a good workout racing up the stairs for favourite rides the Aqua Loop and Super 8 Aqua Racer.
The next day's Buzzsaw ride at Dreamworld was another dive-straight-in start. The trick, said the 15-year-old, is to watch the ride first, Mum - that way there are no nasty surprises.
We make our way round the park's rides, dipping into Whitewater World next door for the Green Room (my favourite), the Wedgie and SuperTubes Hydrocoaster.
The Bro and The Rip we leave to the teenagers before we return with our World Pass to Dreamworld, where even Dad braves the Cyclone Rollercoaster and likes it so much he goes back for seconds.
Mum goes on the twisty-turny Claw, surprising everyone including herself, and we all go on the Motocoaster as a final ride.
We've had our fill of thrills ... well, us parents have. Our youngest seems to have an endless supply of batteries. But that's the fun of it: the teens can do their own thing at the parks, the parents can join in when they find the courage, and then back at the Gold Coast you can surf, swim, cycle, walk, eat ... or just chill if you're a teenager who reckons the best part about a holiday is sleeping in.