The force of Hans, the German Shepherd police dog, running at me from behind and biting my arm, knocked me straight off my feet.
He wasn't even attacking at full pelt, and I knew he was coming for me.
Imagine if you were caught unaware by an attacking dog?
"What we'd suggest is cross your arms and turn your back to them, don't run away- if you run away then you're [encouraging] the dog to... chase you, and you're turning it into a game," explains head of the West Midlands Police Dog Unit, Inspector Leanne Chapman.
Even with the suit protection, fully padded, and covered by protective fabric, it feels like my elbow is bruising as Hans sinks his teeth in. My heart is pounding, I'm breathless. My first reaction would be to run.
"If the dog is biting you, try to keep as still as possible and don't try to fight with the dog," Insp Chapman explains.
"If someone comes and tries to hold their collar to try and stop that ragging reflex in the dog, just try to prevent as much injury as you can."
West Midlands Police, like other force areas across the UK, are dealing with a steep rise in dog attacks - including ones by types of XL bullies.
The government says it is close to banning the breed, because they have been involved in half of the UK's fatal dog attacks in recent years.
They invited Sky News to their dog training grounds at Balsall Common near Coventry to tell us how, in the last six months, their force alone has been called out to 800 dangerous dog-related incidents.
They show us footage of some of the dogs they have seized; "Charles", a white American Cross, "Titan" a brown Pocket Bully, "Hector" a Great Dane Mastiff Cross.
Many of the dogs they seize have caused serious injury to people.
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An XL Bully is shown prowling around a garden in squalor. Due to his size and potential danger to officers, they had to fire a tranquilliser shot to sedate him.
PC Mark Collier, a dog handler with nine years experience, tells me they've had a "massive increase" in attacks.
"To the point where some days you come to work and that's all you do for the whole day, a solid duty of dangerous dog incidents", he says.
"For some of the dogs that we're seizing, and the power of them, you can have two or three handlers struggling to handle some of these dogs."