"Where's the most adventurous place you've had sex?" asks Danielle.
"On the bus," replies Courtney.
"On the bus?" says Danielle, flatly.
"No, in the cinema," says Courtney quickly.
Suddenly, Danielle realises what Courtney has just said. Her eyes widen and her voice rises. "You've had sex on the bus?"
There is no denying the BBC Three-ness of Unsafe Sex in the City. Within the first minute of the documentary series, following staff at the Manchester Centre for Sexual Health, we hear the words "back passage", "shagging everyone" and "pus coming out everywhere". Health centre staff, we are told, are busy "swabbing, probing and examining" patients.
These patients include Courtney, who is aiming to sleep with 40 men by her 18th birthday. She has three months and seven men still to go. Courtney's mother has taken to leaving condoms and sexual health leaflets on her bed; Courtney has taken to ignoring them.
Then there is Kervin, who has come for a check-up after a condom-free one-night stand. "I suppose I should have strapped up, innit?" he says. "I don't like strapping up."
With cameras rolling, Kervin has a swab inserted into his urethra. He is then informed that he has gonorrhoea, and will have to have an injection. In his backside. "In my arse?" he says, over and over. "Bloody hell."
Kervin's best friend Joe, meanwhile, is also at the centre for a check-up. "In the past three months, how many sexual partners have you had?" asks Lauren, the 21-year-old clinician.
Joe flashes his best cheeky grin: "I don't even know where to begin counting." Lauren gives him a long, hard look. By the time the camera cuts away, the milk in my tea has curdled.
Unsafe Sex in the City is, essentially, a cross between Hollyoaks and Embarrassing Bodies. Nonetheless - and I am taking a deep breath before saying this - I think it should be mandatory viewing in schools. Because, as the programme brutally shows, the reality of unsafe sex is one of rectal swabs, drippy willies ("We should probably say 'penis'" one nurse remarks) and blood tests. Very little drives home the risks of unprotected sex like watching a grown man break down on receiving a positive HIV diagnosis.
The ultimate message is so clear that even Joe eventually works it out: "Don't be a fool - wrap your tool." Then he celebrates his sexual all-clear by going out and getting laid.