I'm about to hurtle downhill on a bike from the summit of Mt Tarawera. That's 10km down a 4WD track carved out of a silky and slippery rock that you loll around on rather than stick to. Even though I'm fitted out in armour, with knee and elbow pads, shin and chest guards, and the obligatory helmet and gloves, it's still a little unnerving. It will be my fastest downhill.
We bumped and bounced our way slowly up the road to the summit in a Hilux and crikey, it's steep.
I know what you're thinking. You got a ride up? Well, when you've got a weekend in Rotorua - a mountain biker's mecca - time is precious and thrill-seeking comes first. Besides, it's Sunday afternoon and I'm heading home to Auckland in three hours or so. That leaves just enough time to wander round the top of this sacred mountain, explore the eerie crater and then scorch down its beautiful slopes.
This volcano, which last erupted in 1886, killing 153 people and destroying the Pink and White Terraces, is sacred to the Ngati Rangitihi people, who own it. And, as Nick Chater, my guide today from Multi-Day Adventures, says, it's a special place to start a mountain bike ride from.
"People think Rotorua is about Maori culture, mud pools and geysers but it's places like Tarawera that are the real jewels," he says.
Today, even though it's too cloudy to take in the panoramic views, it's stunning and there's an odd mix of menace and beauty. The mist swirls round the rim of the crater, revealing then concealing the jagged contours, rich red rock, and deep crevasses. It's a spiritual place.
It used to be a public free-for-all up here, and it's hard to believe trail bikers used to hoon around willy-nilly. Now, access is controlled by the management company Mt Tarawera New Zealand and is limited to organised tours such as those run by Multi-Day Adventures.
It costs to come up here - the Volcanic Biking Tour I'm doing costs $299 a person - but it's worth it. You can also ride in a helicopter to the summit, but that costs $610 a person for the four-hour experience.
After a descent into the crater via the short scree run - on which you bound, leap and land like you're weightless - and a meander around the desolate bowl, it's time to "pin it" down the mountain.
At this point I have to say I wouldn't be as amped for this blistering ride if I hadn't have done the MTB skills clinic yesterday with mountain biking experts James Dodds and Gabby Malloy (aka Doddsy and Gabby).
Yes, I probably would have done the Tarawera ride, but I'd either have come to a nasty end on a bend or be going so slow it would be pointless, not to mention boring.
More on my fate on Tarawera later. But first, let's go back to yesterday morning. At 10am I roll into the car park of Whakarewarewa Forest, the launch pad for riders heading out on to the many trails created in the bush.
Apart from being a bit of a wimp at times, I'm a pretty good bike rider. But I was about to change the whole way I ride a bike.
Like most of us, I was taught to lean back as far as I could when riding down a steep drop. That is the first of many mountain biking myths Doddsy and Gabby will destroy today.
No, don't lean back. The proper way to do it is by distributing your weight evenly around your bike. Simple really. The difficult part is achieving this. The key is to have "light hands", a phrase Gabby and Doddsy drum into us throughout the day.
To get "light hands", stand up on the pedals, taking most of your weight on your legs, then move your body backwards and forwards. When your body is positioned properly on the bike your hands will feel "light" - and relaxed - on the hand grips, and surprisingly you'll feel in control because you're in the most stable position on your bike. It's a case of don't fight it, feel it.
Plus, keep that bum out and up when you're standing on the pedals - because that's mostly where you'll be when you're hurtling down a trail.
If you haven't studied the art of bike riding it's probably best to spend a day with the experts. The clinic is not only for novices. Today's group of 18 keen riders is a mix of ages and abilities, and it's a revelation for us all. I even learn to skid properly. And, best of all, the clinic increases my confidence so much that I try jumps, ride down steep drops, and tear through technical trails that previously I would never have attempted.
Sunday morning dawns, and it's time to put what I learned yesterday to the test. First stop before heading up Tarawera are the trails in Whakarewarewa Forest and on Tawa Hill. It's raining, which makes the labyrinth of tracks even more merciless than usual.
But with the mantra of "light hands" pulsing through my brain, I'm ready to tackle trails such as Hot X Bun, the Rollercoaster, and even the muddy chute of death used for the national downhill championships. (I confess, I got off and walked a lot of the chute because it's not extreme, it's ridiculous.)
At 9.30am, we catch one of the Southstar Shuttles - two buses ferrying riders to the top of Tawa Hill - for a morning of riding. The shuttles also do afternoon runs starting at 1pm, and during daylight saving hours a Tuesday night shuttle leaves Burger Fuel in town at 5.15pm and the carpark at 5.30pm and runs until dark.
Purists will scoff at the shuttle, but with the vast maze of tracks on offer, and when you're here for only a weekend, time is valuable. Plus, rest assured your heart rate will be peaking - not only from the adrenalin but because a fair bit of pedalling is involved on crazy root and rut infested trails such as the Billy T (named after the comedian).
But it's no laughing matter when you come across a jump that you're not ready for and it's too late to pull out, and you're flying through the air.
Light hands. Light hands. Bum out and up. Bum out and up.
Surprisingly, with a whoop of horror through gritted teeth, I land safely. I'm ready for it next time and take the by-pass.
My favourite trail is the 2.7 km Hot X Bun, a grade four ride with a perfect combination of long climbs and difficult - and often dangerous - obstacles and drops to take on or avoid. I fall off only three times - once down a bank, and twice because of slippery roots.
Ultimately, though, it's all about applying my new skills and then having the guts to go for the ride.
After a quick change of riding gear, I'm ready for Tarawera.
Nick's main bit of advice before we hurtle down the mountain is to not brake sharply. I won't stop, apparently, because of that slippery rock surface.
"Just do what Gabby and Doddsy told you," he says. "Point that head and body in the direction you want to go and trust the bike. If you brake, quite often you feel like you might be history."
Thanks for the encouragement, Nick. Cheers.
I soon see what he means.
The first part of the downhill is steep, with off-camber corners and sloping sections where you feel as though you're going to slide into the bush. And, the most worrying thing is that your speed gets out of control very easily.
When I try to stop at the DoC office, to sign the visitors' book, I just miss a hokey-looking fence made of manuka and finally come to a halt.
The second part of the downhill is more like a roller coaster, with large stones and bumps to get good air from, and sporadic bits of uneven surface, with nasty slabs of rock sticking out of the road. But with those light hands and my arms out like a real-life downhill racing demon, I glide swiftly over them as if they're not even there.
It's thrilling, at times heart-stopping, but most of all, fun. It's all over too quickly, but the smile lasts for days.
Southstar shuttles leave on Saturday and Sunday at 9.30am and 1pm from the Waipa MTB carpark (off SH5 heading out of Rotorua towards Taupo). On Tuesday nights, catch it from Burger Fuel in town at 5.15pm, or MTB carpark at 5.30pm. From December 27 the shuttles will run for 10 days continuously. Go to www.southstaradventures.com.
$5 a run, $25 for the morning, $40 full day.
Multi-Day Adventures 4WD Volcanic Bike is $299 a person. Booking information on (07) 362 4399 or go to www.multidayadventures.co.nz
MTB Skills Clinic - the fundamentals of mountain biking full day course costs $115 a person. Go to www.mtbskillsclinics.co.nz.
For more information on Mt Tarawera, see www.mttarawera.co.nz